U

 

Marketing and

Regulatory

Programs

Agricultural

Marketing

Service

Specialty

Crops

Program

Specialty 

Crops 

Inspection

Division

AIM 

Inspection

Series

Technical Procedures 

Manual 

June 2020
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i 

Document Title

Table of Contents

INTRODUCTION .......................................................................................................................... 1

GUIDE FOR ELECTRONIC USAGE........................................................................................... 2

STANDARD LABORATORY PROCEDURES DOCUMENTS AND INDEX .......................... 2

ACID TITRATION ........................................................................................................................ 3

Acid Conversion Chart for Fruit Juices .......................................................................................... 6

AFLATOXIN ANALYSIS OF PEANUT BUTTER AND OTHER PEANUT PRODUCTS ..... 11

Sampling ....................................................................................................................................... 12

Other Products .............................................................................................................................. 12

Aflatoxin Failure Re-inspection Procedure .................................................................................. 13

ATTRIBUTES .............................................................................................................................. 17

BRIX MEASUREMENT.............................................................................................................. 17

Fresh Products ........................................................................................................................... 17

Processed Products ................................................................................................................... 17

Liquid Packing Medium ........................................................................................................... 18

Inspection and Certification Criteria ......................................................................................... 18

Acceptance Criteria ................................................................................................................... 19

Preparation of Samples ............................................................................................................. 19

FDA Established Minimum Brix Levels .................................................................................. 28

TEMPERATURE CORRECTIONS FOR OBTAINING BRIX FROM REFRACTOMETER 

READINGS .............................................................................................................................. 30

SUCROSE CONVERSION TABLE ........................................................................................ 31

CALIBRATION OF EQUIPMENT ............................................................................................. 56

Thermometers ............................................................................................................................... 56

Fresh Products ........................................................................................................................... 56

Processed Products ................................................................................................................... 56

Scales ............................................................................................................................................ 56

Fresh Products ........................................................................................................................... 56

Processed Product ..................................................................................................................... 57

Refractometer ................................................................................................................................ 57

Fresh Products ........................................................................................................................... 57

Processed Products ................................................................................................................... 58

pH Meter ................................................................................................................................... 61

Analytical Glassware ................................................................................................................ 61

Hydrometer ............................................................................................................................... 62

Salometer .................................................................................................................................. 66

Colorimeters .............................................................................................................................. 71

CONTAINER INFORMATION .................................................................................................. 72

Sizes of metal containers .......................................................................................................... 72

Explanation of Dimensional Food Can Standards .................................................................... 74

Net contents and fluid measure ................................................................................................. 76

Conversion factors for canned foods ........................................................................................ 76

Sizes of glass containers ........................................................................................................... 78

Calculating drained weight for unpublished container sizes ........................................................ 79

Procedure to Determine the Water Capacity ............................................................................ 80
ii

Containers for frozen fruits and vegetables .............................................................................. 81

Approximate shipping weights ................................................................................................. 83

ENZYME INACTIVATION ........................................................................................................ 87

Lot Inspection Procedures ........................................................................................................ 87

In-Plant Inspection Procedures ................................................................................................. 87

Quality Control Testing – Unofficial ........................................................................................ 88

Special Tests for Certain Products ............................................................................................ 88

Peroxidase Testing Procedure ................................................................................................... 89

Catalase Testing Procedure ....................................................................................................... 91

FROZEN AND REFRIGERATED PRODUCT ........................................................................... 93

Inspection Request ........................................................................................................................ 94

Sampling ....................................................................................................................................... 94

Equipment used for Checking Temperatures ................................................................................ 94

Selecting Representative Samples ................................................................................................ 95

Method I - Measuring Temperatures by Opening Samples .......................................................... 96

Method II – Measuring Temperatures without Opening Samples ................................................ 97

Thawing Procedures...................................................................................................................... 98

Verification of Frozen Sample Units .......................................................................................... 101

Cooking Procedures ................................................................................................................ 104

FRUIT – SUGAR RATIO .......................................................................................................... 106

Verification of Fruit – Sugar Ratio: In-Plant Inspection ....................................................... 108

Verification of Fruit – Sugar Ratio: Lot Inspection ............................................................... 113

Determining Lot Acceptance ...................................................................................................... 116

GOOD COMMERCIAL PRACTICES ...................................................................................... 117

Counts ..................................................................................................................................... 117

Range of Counts Guide for Good Commercial Practice ......................................................... 117

Specific Count Guide for Good Commercial Practice ............................................................ 118

DRAINED WEIGHT .................................................................................................................. 118

Limits of Good Commercial Practice ..................................................................................... 119

Determination of "Unreasonable Shortage"............................................................................ 119

Averaging Drained Weights of Codes within a Lot ............................................................... 120

Procedures for Frozen Products In-Plant or Lot Inspection ................................................... 120

FILL OF CONTAINER .............................................................................................................. 124

Criteria for Determining "Fill of Container" .......................................................................... 124

NET WEIGHT ............................................................................................................................ 128

Fresh Products ......................................................................................................................... 128

Processed Products ................................................................................................................. 128

VACUUM READINGS.............................................................................................................. 131

MACROANALYTICAL PROCEDURES ................................................................................. 133

SALT DETERMINATION ........................................................................................................ 133

Glassware and Equipment ...................................................................................................... 134

Terminology ............................................................................................................................ 134

Methodology and Reagents .................................................................................................... 134

Mohr Method Reagents: ......................................................................................................... 135

Volhard Method Reagents: ..................................................................................................... 136

Visual Indicator Methods ............................................................................................................ 137

Mohr Method .......................................................................................................................... 137
iii

Volhard Method ...................................................................................................................... 139

Potentiometer (pH meter) Method .............................................................................................. 141

Equipment ............................................................................................................................... 141

Electrode Attachment ............................................................................................................. 141

Reagents .................................................................................................................................. 142

Standardization ....................................................................................................................... 142

Preparation of Sample ............................................................................................................. 143

Determination ......................................................................................................................... 143

Conductivity (salt meter) Method ............................................................................................... 143

REFERENCE LINKS ................................................................................................................. 145

APPENDIX I-Thermometer Checks Log ................................................................................... 146

APPENDIX II - Weekly Gram Scale Checks Log ..................................................................... 147

APPENDIX III - Weekly Ounce Scale Checks Log ................................................................... 148

APPENDIX IV - Refractometer Checks Log ............................................................................. 149

APPENDIX V - Daily pH Meter Checks Log ............................................................................ 150

APPENDIX VI - Analytical Glassware Checks Log .................................................................. 151

APPENDIX VII - Hydrometer Checks Log ............................................................................... 152

APPENDIX VIII - Salometer Checks Log ................................................................................. 153

APPENDIX IX - Colorimeter Calibration Checks Log - Hunter D45 ....................................... 154

APPENDIX X - Colorimeter Calibration Checks Log - Hunter D45D5 .................................... 155

APPENDIX XI - Colorimeter Calibration Checks Log - Macbeth Color-Eye 3000, 3100, and i5

..................................................................................................................................................... 156

APPENDIX XII - Example: Optional Worksheet for Fruit/Sugar Ratio. .................................. 157
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 1 of 157

INTRODUCTION

This document is designed to give guidance to Specialty Crops Inspection (SCI) Division 

personnel of the United States Department of Agriculture (USDA), and promote uniformity in the 

procedures covered. These procedures are an integral part of SCI services. If needed, contact 

your immediate supervisor for any situation not addressed in this manual. 

Compliance with the Agricultural Marketing Service (AMS) guidelines does not excuse failure to 

comply with the Food, Drug, and Cosmetic Act or any other applicable Federal or State laws or 

regulations. SCI Division of the Specialty Crops Programs (SC), AMS is responsible for 

grading/inspecting, audits and standardization programs of fresh and/or processed fruits and 

vegetables and related products. The legal authority for grading, auditing and standardization 

activities are the Agricultural Marketing Acts of 1936 and 1946, as amended. 

Applicants may obtain inspections of any fresh and/or processed fruit and vegetable and related 

products for which they have a financial interest. The inspection service is voluntary and 

self-supporting and is offered on a fee-for-service basis.

These procedures were developed for processed commodities and in some instances may be 

applied to fresh commodities when a procedure is not already established within a separate SCI 

document pertaining to fresh commodities (i.e. General Market Manual). When a procedure is 

established within a separate SCI document pertaining to fresh commodities, that procedure will 

be followed. 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 2 of 157

GUIDE FOR ELECTRONIC USAGE 

The AIM system of instructional manuals is available electronically in Adobe Acrobat Portable 

Document Format (PDF) at the following intranet address: 

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hypertext in the Table of Contents allows a reader to go directly to the section of interest in the 

manual by clicking on the section title. 

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STANDARD LABORATORY PROCEDURES DOCUMENTS AND INDEX 

The SCI Division Standard Laboratory Procedures Documents are a series of documents designed 

to standardize Division processed product laboratory practices. Included with these documents is 

an Index to associate the various products graded with the SCI Standard Laboratory Procedures 

Documents. The Index acts a quick reference to the Documents and are intended to work in 

harmony with current guidance. The Index allows for better uniformity and consistency among 

the various commodities and technical procedures SCI offices perform. Use of the Index and 

associated Standard Laboratory Procedures Documents whenever possible. The Documents may 

also be printed and posted at individual grading areas for quick reference when electronic access 

is not practical.

The SCI Division Standard Laboratory Procedures documents are available on the AIM 

Inspection site/Inspection Resources/AIM Inspection Series Processed Products/Inspection/SCI 

Standard Laboratory Procedures, and at the following intranet link: \\usda.net\ams\SCSCI\SCIAIM\Inspection\LabSTP\SCI_Standard_Laboratory_Procedures.pdf. 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 3 of 157

ACID TITRATION

An acid is a substance that dissociates in a solution to give hydrogen ions. The higher the 

hydrogen-ion concentration, the stronger the acid; the lower the concentration, the weaker the acid. 

Acids are sour to the taste and occur naturally in most fruits and vegetables. Acids are also added 

to processed products to inhibit the growth of mold and bacteria, and as flavor enhancers. 

Total acidity is usually determined by titration with a weak base, such as 0.1N sodium hydroxide. 

This is a neutralization reaction resulting in the formation of water and “salts” derived from the 

particular acid involved. As the acid and base react, the hydrogen-ion concentration (pH) 

decreases until an equivalent amount of base has been added. At this point the pH value of the 

solution is not neutral (pH 7) as inferred by the name “neutralization reaction” but is slightly basic 

due to the hydrolysis of the salts. Using the neutralization reaction, total acidity may be measured 

visually with the use of an indicator, or potentiometrically with a pH meter.

Composition of Some Common Acids 

Acid Molecular Wt. Valence Equivalent Wt. Acid factor

Acetic 60.05 1 60.1 .0601 

Citric 192.12 3 64.0 .0640 

Malic 134.09 2 67.0 .0670 

Tartaric 150.09 2 75.0 .0750 

A. Sample Preparation

Note: Use distilled or deionized water in the preparation of samples. 

1. Fruit and Vegetable Juices

Review the appropriate U.S. grade standards and/or specifications to determine the 

following: 

a. Are the results to be determined as weight/weight or weight/volume? 

b. Are concentrated samples to be reconstituted before taking aliquot for 

analysis?

c. Which acid will results be expressed, e.g. malic, tartaric, citric?

Mix the sample thoroughly and pipette 10.0 ml (or weigh 10.0g) of the 

sample into a 250 ml beaker or flask and add approximately 100 ml of 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 4 of 157

water. Proceed with determination as described in “C. Procedures” on the 

following page. 

2. Mustard and Sauces 

Mix the sample thoroughly. Weigh 10.0g of the sample into a 200 ml volumetric 

flask and dilute to volume with water. Shake well and filter through a dry fluted

paper filter. Determine acidity on 100 ml of filtrate using 0.1N NaOH and express 

results as acetic acid.

3. Mayonnaise, Salad Dressing and Dressings for Foods 

Weigh 15.0g of the sample into a 500 ml Erlenmeyer flask and dilute with 200 ml 

of water. Shake until all lumps are thoroughly broken up. Determine acidity using 

the visual indicator method, titrating with 0.1N NaOH. To recognize the endpoint, 

you may wish to have a duplicate sample nearby so that the first color change will 

be evident by comparison. Express results as acetic acid. 

4. Vinegar

Pipette 10.0 ml of the sample into a 500 ml Erlenmeyer flask and dilute with water 

until the vinegar is only slightly colored. Determine acidity using the visual 

indicator method, titrating with 0.5N NaOH. Express the results as acetic acid.

5. Vitamin C (Ascorbic Acid)

Ascorbic acid is a white or yellow crystal powder with a molecular weight of 

176.12 grams. It is odorless but has a pleasant, sharp, acidic taste. Ascorbic acid 

is relatively unstable and is easily oxidized upon exposure to air and light. It 

occurs naturally in many fruits and vegetables and is abundant in freshly harvested 

produce. 

The Division does not routinely test for ascorbic acid, and the reagents for this test 

are different from reagents for other acid titrations. If you are asked to perform a 

Vitamin C test, contact your supervisor for guidance. 

 

B. Preparation of Phenolphthalein Indicator 

Dissolve 1 gram (g) of phenolphthalein in 50 milliliters (ml) of 95% ethyl alcohol 

and add 50 ml of water. 

C. Procedures

 1. Visual Indicator Method 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 5 of 157

This method is useful for light colored samples that will allow the inspector to 

detect the faint pink end point color change of phenolphthalein. 

a. Fill a clean burette with the appropriate standard NaOH solution. 

b. Drain the solution meniscus to the 0.0 ml mark. Take readings with your 

eyes at the level of the meniscus, measuring at the lowest point of the 

meniscus. 

c. Add two or three drops of phenolphthalein indicator to the prepared sample 

and place under the burette. If possible, the burette tip should be 

approximately 1 inch from the surface of the sample.

d. Titrate the sample by running the solution from the burette slowly but 

steadily while swirling or stirring the sample gently. Near the end point, 

the local color change diffuses more and more slowly through the sample. 

At this point, run the solution from the burette one drop at a time until the 

sample is a faint pink color, indicating that the end point has been reached. 

e. Read the burette at the lowest point of the meniscus. Record this as the 

volume of NaOH used. Use this figure to calculate total acidity. See 

“D. Calculations” on the following page. 

f. If the amount of NaOH used is less than 10 ml or more than 50 ml, adjust 

the sample size accordingly so that the titration will fall within that range.

g. At the discretion of the supervisor, the titration may be repeated and the 

results averaged. Titrations should agree within 0.1 ml. 

2. Potentiometric Method (pH) 

 This method may be used for determining the acidity on any sample solution, 

regardless of color. 

a. Standardize the pH meter according to the manufacturer’s instructions 

using a commercial pH 7 buffer solution. 

b. After standardizing the instrument, rinse the electrode thoroughly with 

water and submerge in the sample.

c. Fill the burette with the appropriate standard NaOH as shown in Visual 

Indicator Method, steps a, and b. 

d. Stir moderately by hand or with a magnetic stirrer.

e. Add NaOH rapidly until near pH 6, and then slowly add until reaching 

pH 7. 

f. After pH 7 is reached, titrate by adding NaOH very slowly, a few drops at a 

time. Allow the sample to mix before adding more.
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 6 of 157

g. Continue titrating to the end point of pH 8.1 (± 0.2); add NaOH one drop at a time 

because the pH will change more rapidly with each addition. (Procedural 

Reference - AOAC Official Method Acidity (Titratable) of Fruit Products) 

Record the volume of NaOH used to reach pH 8.1, reading the burette at 

the lowest point of the meniscus. Use this figure to calculate the total 

acidity. See “D. Calculations.” below.

h. Titrations should be between 10 ml and 50 ml. If not, adjust the sample 

size and re-titrate.

i. At the discretion of the supervisor, the titration may be repeated, and the 

results averaged. Titrations should agree within 0.1 ml. 

D. Calculations

Total acidity is calculated as the predominant acid in the sample.

 1. Total Acidity (weight/volume)

 Total Acidity, g/100 ml = T x N x A x 100 

 V

 Where T = ml NaOH used

 N = Normality of NaOH used

A = Acid factor

 V = Volume of the sample 

 2. Total Acidity (weight/weight)

 Total Acidity, g/100 g = T x N x A x 100

 W 

 Where T = ml NaOH used

 N = Normality of NaOH used

A = Acid factor

W = Weight of the sample

Acid Conversion Chart for Fruit Juices 

Acid content and Brix/acid ratio limits in most USDA grade standards for fruit juices are based on 

acid expressed as “grams per 100 grams of juice” (or percent by weight) rather than “grams per 

100 ml of juice” (or percent by volume). When expressed in this manner, acid content calculated 

as wt/vol must be converted to wt/wt before determining acid compliance or calculating Brix/acid 

ratio. This may be accomplished by using a formula with the specific gravity of the juice. 

The following conversion chart is based on this formula and provides a convenient means for 

converting the acid content of fruit juices from weight/volume to weight/weight. 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 7 of 157

A. How to Use the Chart 

 1. Determine the acid content (wt/vol) of the juice.

 2. Determine the Brix value of the juice.

3. Find the acid wt/vol value on the chart. Following a straight line to the right, find 

the Brix Range columns containing the Brix value of the juice. (There are three 

sets of Brix Range columns on the chart.) 

4. The corresponding acid wt/wt value is shown in the column to the right of the Brix 

Range columns.

Example: Acid after titration = 0.75 grams/100ml (wt/vol)

 

 Brix of juice = 11.8°

 Acid from the chart = 0.72 grams/100 grams (wt/wt) 

 The true Brix acid ratio would be as follows: 

 11.8 

 0.72 = 16.4:1 

The charts are abbreviated for convenience. If the acid wt/vol or Brix of the juice is not 

covered by these charts, the acid wt/wt may be obtained by the following formula:

 Acid Wt/Vol . 

 Specific Gravity of the juice = Acid Wt/Wt

The specific gravity of the juice may be obtained from the Brix reading by use of the 

“Sucrose Conversion Table” found in the “Brix” section of this instructional manual.
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 8 of 157

ACID CONVERSION CHART – FRUIT JUICES

From Grams/100 ML (WT/VOL) to Grams/100 Grams (WT/WT)

Acid

wt/vol

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Brix Range Acid

Minimum Maximum Minimum Maximum Minimum Maximum wt/wt

0.50

0.51

0.52

7.0

7.0

7.0

7.7

7.6

7.4

0.49

0.50

0.51

7.8

7.7

7.5

13.0

12.7

12.5

0.48

0.49

0.50

13.1

12.8

12.6

17.0

17.0

17.0

0.47

0.48

0.49

0.53

0.54

0.55

7.0

7.0

7.0

7.3

7.2

7.0

0.52

0.53

0.54

7.4

7.3

7.1

12.2

12.0

11.8

0.51

0.52

0.53

12.3

12.1

11.9

17.0

16.8

16.5

0.50

0.51

0.52

0.56

0.57

0.58

7.0

7.0

7.0

11.6

11.4

11.2

0.54

0.55

0.56

11.7

11.5

11.3

16.2

16.0

15.7

0.53

0.54

0.55

16.3

16.1

15.8

17.0

17.0

17.0

0.52

0.53

0.54

0.59

0.60

0.61

7.0

7.0

7.0

11.0

10.8

10.6

0.57

0.58

0.59

11.1

10.9

10.7

15.4

15.1

14.9

0.56

0.57

0.58

15.5

15.2

15.0

17.0

17.0

17.0

0.55

0.56

0.57

0.62

0.63

0.64

7.0

7.0

7.0

10.4

10.3

10.1

0.60

0.61

0.62

10.5

10.4

10.2

14.7

14.4

14.2

0.59

0.60

0.61

14.8

14.5

14.3

17.0

17.0

17.0

0.58

0.59

0.60

0.65

0.66

0.67

7.0

7.0

7.0

9..9

9.8

9.6

0.63

0.64

0.65

10.0

9.9

9.7

14.0

13.8

13.5

0.62

0.63

0.64

14.1

13.9

13.6

17.0

17.0

17.0

0.61

0.62

0.63

0.68

0.69

0.70

7.0

7.0

9.3

9.5

9.4

13.0

0.66

0.67

0.67

9.6

9.5

13.1

13.3

13.2

16.7

0.65

0.66

0.66

13.4

13.3

16.8

17.0

17.0

17.0

0.64

0.65

0.65

0.71

0.72

0.73

9.2

9.1

8.9

12.8

12.6

12.4

0.68

0.69

0.70

12.9

12.7

12.5

16.5

16.2

16.0

0.67

0.68

0.69

16.6

16.3

16.1

17.0

17.0

17.0

0.66

0.67

0.68

0.74

0.75

0.76

8.8

8.7

8.6

12.3

12.1

11.9

0.71

0.72

0.73

12.4

12.2

12.0

15.8

15.6

15.4

0.70

0.71

0.72

15.9

15.7

15.5

17.0

17.0

17.0

0.69

0.70

0.71

0.77

0.78

0.79

8.5

8.4

8.3

11.8

11.6

11.5

0.74

0.75

0.76

11.9

11.7

11.6

15.2

15.0

14.8

0.73

0.74

0.75

15.3

15.1

14.9

17.0

17.0

17.0

0.72

0.73

0.74

0.80

0.81

0.82

0.83

8.2

8.1

8.0

7.9

11.3

11.2

11.0

10.9

0.77

0.78

0.79

0.80

11.4

11.3

11.1

11.0

14.6

14.4

14.2

14.1

0.76

0.77

0.78

0.79

14.7

14.5

14.3

14.2

17.0

17.0

17.0

17.0

0.75

0.76

0.77

0.78

0.84

0.85

0.86

0.87

7.8

7.7

7.6

7.5

10.8

10.7

10.5

10.4

0.81

0.82

0.83

0.84

10.9

10.8

10.6

10.5

13.9

13.7

13.6

13.4

0.80

0.81

0.82

0.83

14.0

13.8

13.7

13.5

17.0

16.8

16.6

16.4

0.79

0.80

0.81

0.82

0.88

0.89

0.90

7.4

7.3

7.3

10.3

10.2

10.1

0.85

0.86

0.87

10.4

10.3

10.2

13.3

13.1

13.0

0.84

0.85

0.86

13.4

13.2

13.1

16/2

16.1

15.9

0.83

0.84

0.85
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 9 of 157

Acid

wt/vol

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Minimum Maximum Minimum Maximum Minimum Maximum

0.91

0.92

0.93

7.2

7.1

7.0

9.9

9.8

9.7

0.88

0.89

0.90

10.0

9.9

9.8

12.8

12.7

12.5

0.87

0.88

0.89

12.9

12.8

12.6

15.7

15.5

15.4

0.86

0.87

0.88

0.94

0.95

0.96

7.0

7.0

7.0

9.6

9.5

9.4

0.91

0.92

0.93

9.7

9.6

9.5

12.4

12.3

12.1

0.90

0.91

0.92

12.5

12.4

12.2

15.2

15.0

14.9

0.89

0.90

0.91

0.97

0.98

0.99

7.0

7.0

7.0

9.3

9.2

9.1

0.94

0.95

0.96

9.4

9.3

9.2

12.0

11.9

11.8

0.93

0.94

0.95

12.1

12.0

11.9

14.7

14.6

14.4

0.92

0.93

0.94

1.00

1.01

1.02

7.0

9.0

9.0

9.0

11.5

11.4

0.97

0.97

0.98

9.1

11.6

11.5

11.7

14.1

14.0

0.96

0.96

0.97

11.8

14.2

14.1

14.3

16.7

16.6

0.95

0.95

0.96

1.03

1.04

1.05

8.9

8.8

8.7

11.3

11.2

11.1

0.99

1.00

1.01

11.4

11.3

11.2

13.9

13.7

13.6

0.98

0.99

1.00

14.0

13.8

13.7

16.4

16.2

16.1

0.97

0.98

0.99

1.06

1.07

1.08

8.6

8.5

8.5

11.0

10.9

10.8

1.02

1.03

1.04

11.1

11.0

10.9

13.5

13.3

13.2

1.01

1.02

1.03

13.6

13.4

13.3

15.9

15.8

15.6

1.00

1.01

1.02

1.09

1.10

1.11

8.4

8.3

8.2

10.7

10.6

10.5

1.05

1.06

1.07

10.8

10.7

10.6

13.1

13.0

12.8

1.04

1.05

1.06

13.2

13.1

12.9

15.5

15.3

15.2

1.03

1.04

1.05

1.12

1.13

1.14

8.2

8.1

8.0

10.4

10.3

10.2

1.08

1.09

1.10

10.5

10.4

10.3

12.7

12.6

12.5

1.07

1.08

1.09

12.8

12.7

12.6

15.1

14.9

14.8

1.06

1.07

1.08

1.15

1.16

1.17

8.0

7.9

7.8

10.1

10.0

9.9

1.11

1.12

1.13

10.2

10.1

10.0

12.4

12.3

12.2

1.10

1.11

1.12

12.5

12.4

12.3

14.7

14.5

14.4

1.09

1.10

1.11

1.18

1.19

1.20

7.7

7.7

7.6

9.9

9.8

9.7

1.14

1.15

1.16

10.0

9.9

9.8

12.1

12.0

11.9

1.13

1.14

1.15

12.2

12.1

12.0

14.3

14.2

14.1

1.12

1.13

1.14

1.21

1.22

1.23

7.6

7.5

7.4

9.6

9.5

9.5

1.17

1.18

1.19

9.7

9.6

9.6

11.8

11.7

11.6

1.16

1.17

1.18

11.9

11.8

11.7

13.9

13.8

13.7

1.15

1.16

1.17

1.24

1.25

1.26

7.4

9.4

9.3

9.4

11.4

11.3

1.20

1.20

1.21

9.5

11.5

11.4

11.5

13.5

13.4

1.19

1.19

1.20

11.6

13.6

13.5

13.6

15.6

15.5

1.18

1.18

1.19

1.27

1.28

1.29

9.3

9.2

9.1

11.2

11.1

11.0

1.22

1.23

1.24

11.3

11.2

11.1

13.3

13.2

13.1

1.21

1.22

1.23

13.4

13.3

13.2

15.3

15.2

15.1

1.20

1.21

1.22

1.30

1.31

1.32

9.0

9.0

8.9

10.9

10.9

10.8

1.25

1.26

1.27

11.0

11.0

10.9

13.0

12.9

12.8

1.24

1.25

1.26

13.1

13.0

12.9

15.0

14.9

14.7

1.23

1.24

1.25
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 10 of 157

Acid

wt/vol

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Minimum Maximum Minimum Maximum Minimum Maximum

1.33

1.34

1.35

8.8

8.8

8.7

10.7

10.6

10.5

1.28

1.29

1.30

10.8

10.7

10.6

12.7

12.6

12.5

1.27

1.28

1.29

12.8

12.7

12.6

14.6

14.5

14.4

1.26

1.27

1.28

1.36

1.37

1.38

8.6

8.6

8.5

10.5

10.4

10.3

1.31

1.32

1.33

10.6

10.5

10.4

12.4

12.3

12.2

1.30

1.31

1.32

12.5

12.4

12.3

14.3

14.2

14.1

1.29

1.30

1.31

1.39

1.40

1.41

10.3

10.3

10.2

12.1

12.0

11.9

1.33

1.34

1.35

12.2

12.1

12.0

14.0

13.9

13.8

1.32

1.33

1.34

14.1

14.0

13.9

15.9

15.8

15.7

1.31

1.32

1.33

1.42

1.43

1.44

10.1

10.0

10.0

11.9

11.8

11.7

1.36

1.37

1.38

12.0

11.9

11.8

13.7

13.6

13.5

1.35

1.36

1.37

13.8

13.7

13.6

15.5

15.4

15.3

1.34

1.35

1.36

1.45

1.46

1.47

9.9

9.8

9.8

11.6

11.5

11.4

1.39

1.40

1.41

11.7

11.6

11.5

13.4

13.3

13.2

1.38

1.39

1.40

13.5

13.4

13.3

15.2

15.1

15.0

1.37

1.38

1.39

1.48

1.49

1.50

9.7

9.6

11.3

11.4

11.3

13.0

1.42

1.43

1.43

11.5

11.4

13.1

13.1

13.0

14.7

1.41

1.42

1.42

13.2

13.1

14.8

14.9

14.8

16.5

1.40

1.41

1.41

1.51

1.52

1.53

11.2

11.2

11.1

12.9

12.8

12.7

1.44

1.45

1.46

13.0

12.9

12.8

14.6

14.5

14.4

1.43

1.44

1.45

14.7

14.6

14.5

16.3

16.2

16.1

1.42

1.43

1.44

1.54

1.55

1.56

11.0

11.0

10.9

12.6

12.5

12.5

1.47

1.48

1.49

12.7

12.6

12.6

14.3

14.2

14.1

1.46

1.47

1.48

14.4

14.3

14.2

16.0

15.9

15.8

1.45

1.46

1.47

1.57

1.58

1.59

10.8

10.7

10.7

12.4

12.3

12.2

1.50

1.51

1.52

12.5

12.4

12.3

14.0

14.0

13.9

1.49

1.50

1.51

14.1

14.1

14.0

15.7

15.6

15.5

1.48

1.49

1.50

1.60

1.61

1.62

10.6

10.5

10.5

12.1

12.1

12.0

1.53

1.54

1.55

12.2

12.2

12.1

13.8

13.7

13.6

1.52

1.53

1.54

13.9

13.8

13.7

15.4

15.3

15.2

1.51

1.52

1.53

1.63

1.64

1.65

10.4

10.3

10.3

11.9

11.8

11.8

1.56

1.57

1.58

12.0

11.9

11.9

13.5

13.4

13.4

1.55

1.56

1.57

13.6

13.5

13.5

15.1

15.0

14.9

1.54

1.55

1.56

1.66

1.67

1.68

10.2

11.7

11.7

11.7

13.2

13.1

1.59

1.59

1.60

11.8

13.3

13.2

13.3

14.8

14.7

1.58

1.58

1.59

13.4

14.9

14.8

14.9

16.3

16.2

1.57

1.57

1.58

1.69

1.70

1.71

11.6

11.5

11.5

13.0

13.0

12.9

1.61

1.62

1.63

13.1

13.1

13.0

14.6

14.5

14.4

1.60

1.61

1.62

14.7

14.6

14.5

16.1

16.0

16.0

1.59

1.60

1.61

1.72

1.73

1.74

11.4

11.3

11.3

12.8

12.7

12.7

1.64

1.65

1.66

12.9

12.8

12.8

14.3

14.2

14.2

1.63

1.64

1.65

14.4

14.3

14.3

15.9

15.8

15.7

1.62

1.63

1.64
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 11 of 157

Acid

wt/vol

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt

Brix Range Acid

wt/wt Minimum Maximum Minimum Maximum Minimum Maximum

1.75

1.76

1.77

11.2

11.1

11.1

12.6

12.5

12.4

1.67

1.68

1.69

12.7

12.6

12.5

14.1

14.0

13.9

1.66

1.67

1.68

14.2

14.1

14.0

15.6

15.5

15.4

1.65

1.66

1.67

1.78

1.79

1.80

11.0

10.9

10.9

12.4

12.3

12.2

1.70

1.71

1.72

12.5

12.4

12.3

13.8

13.8

13.7

1.69

1.70

1.71

13.9

13.9

13.8

15.3

15.2

15.1

1.68

1.69

1.70

1.81

1.82

1.83

10.8

10.8

10.7

12.2

12.1

12.0

1.73

1.74

1.75

12.3

12.2

12.1

13.6

13.5

13.5

1.72

1.73

1.74

13.7

13.6

13.6

15.1

15.0

14.9

1.71

1.72

1.73

1.84

1.85

1.86

12.1

12.0

11.9

13.4

13.3

13.2

1.75

1.76

1.77

13.5

13.4

13.3

14.8

14.7

14.7

1.74

1.75

1.76

14.9

14.8

14.8

16.2

16.1

16.1

1.73

1.74

1.75

1.87

1.88

1.89

11.9

11.8

11.7

13.2

13.1

13.0

1.78

1.79

1.80

13.3

13.2

13.1

14.6

14.5

14.4

1.77

1.78

1.79

14.7

14.6

14.5

16.0

15.9

15.8

1.76

1.77

1.78

1.90

1.91

1.92

11.7

11.6

11.6

13.0

12.9

12.8

1.81

1.82

1.83

13.1

13.0

12.9

14.3

14.3

14.2

1.80

1.81

1.82

14.4

14.4

14.3

15.7

15.6

15.6

1.79

1.80

1.81

1.93

1.94

1.95

11.5

12.8

12.7

12.8

14.0

14.0

1.84

1.84

1.85

12.9

14.1

14.1

14.1

15.4

15.3

1.83

1.83

1.84

14.2

15.5

15.4

15.5

16.7

16.7

1.82

1.82

1.83

1.96

1.97

1.98

12.7

12.6

12.5

13.9

13.8

13.8

1.86

1.87

1.88

14.0

13.9

13.9

15.2

15.2

15.1

1.85

1.86

1.87

15.3

15.3

15.2

16.6

16.5

16.4

1.84

1.85

1.86

1.99

2.00

12.5

12.4

13.7

13.6

1.89

1.90

13.8

13.7

15.0

14.9

1.88

1.89

15.1

15.0

16.3

16.2

1.87

1.88

AFLATOXIN ANALYSIS OF PEANUT BUTTER AND OTHER PEANUT PRODUCTS 

To ensure that peanut products are in compliance with the Food and Drug Administration (FDA) 

guidelines, aflatoxin testing must be done. All Peanut Butter that is graded and all Peanut 

Products that are inspected for quality will be chemically tested for the presence of 

aflatoxin. Peanut butter is the only processed peanut product for which a U.S. standard has been 

issued. However, neither the U.S. Standards for Grades of Peanut Butter, nor the Grading Manual 

for Peanut Butter makes a reference to aflatoxin. Other products such as roasted peanuts, peanut 

granules, peanut flour, etc. are inspected against the requirements contained in contracts, 

announcements, federal specifications, and other specifications or instructions. These documents 

may or may not include aflatoxin testing as a part of inspection.

FDA has an administrative guideline of a maximum of 20 parts per billion (ppb) in processed 

peanut products. Since good manufacturing practices will remove sufficient aflatoxin to result in 

a level of 20 ppb aflatoxin in processed peanut products, the Memorandum of Agreement between 

the Agricultural Marketing Service and FDA (MOU 225-96-2001 – which may be found at the 

following internet address: 

http://www.fda.gov/AboutFDA/PartnershipsCollaborations/MemorandaofUnderstandingMOUs/D

omesticMOUs/default.htm permits a level of 25 ppb aflatoxin in raw peanuts.
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 12 of 157

Any product that fails to meet the FDA guidelines for aflatoxin shall be placed on hold for 

reexamination and/or possible destruction regardless of the source of the original samples. This 

includes product represented by samples submitted by the applicant. Under these circumstances, 

the product to be placed on hold would be the lot as declared by the applicant at the request for 

inspection. All samples for reexamination shall be officially drawn. 

Sampling

Samples shall be drawn for quality in accordance with the regulations. Samples for analysis shall 

be composited from the sample units drawn for quality, provided sufficient product is available 

after inspection. If these sample units will not provide a sufficient quantity of product, parallel 

sample units shall be drawn. Composite samples shall be made as indicated in the table below, 

based on the number of sample units drawn for quality. 

Sampling Rate for Aflatoxin

Sample Size (from the Regulations) 3 6 13 21 29 

No. of Composite Samples (minimum) 1 1 2 3 4 

The composite samples shall be made from approximately equal portions of each sample 

unit. The composite samples shall be of the following minimum size for each product: 

Roasted peanuts – 48 pounds - Peanut granules – 48 pounds - Peanut Butter – 1 pound 

Aflatoxin samples drawn should be sent to the AMS Science and Technology Programs 

(S&T) Aflatoxin Laboratory: 

Blakely Laboratory

6567 Chancey Mill Road 

Blakely, GA 39823 

Laboratory Supervisor 

Phone (229) 723-4570 

Fax (229) 723-7251 

Most specifications that include aflatoxin testing as a requirement state that aflatoxin must 

be negative. In no case may the specification permit a higher level of aflatoxin than 

permitted by FDA.

Certification of peanut products will be withheld until aflatoxin results are obtained from 

the laboratory. 

Other Products

Inspection requests may be received for processed peanut products other than peanut butter, 

roasted peanuts, and peanut granules. In addition to peanut products, other nut products often 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 13 of 157

have aflatoxin requirements. Under these circumstances, the Regional office should contact the 

National office for proper sampling and analysis procedures. 

Aflatoxin Failure Re-inspection Procedure

A. The S&T aflatoxin laboratory notifies their Technical Services Branch (TSB) and the SCI 

Division field office of failed product. The notification may be given by telephone, with a 

follow-up in writing by fax or by email.

B. The SCI Division field office that graded the product will immediately notify the 

Inspection Operations in Washington, DC by telephone to report the following: 

 1. Contractor's name;

 2. Plant location;

 3. Product; 

 4. Date packed;

 5. Codes; 

 6. Quantity; and 

 7. Reason for failure.

Verbal notification should be followed up with an email containing the same information. 

Send the email to Inspection Operations in Washington DC and (based on location) the 

Eastern, Central, or Western Regional office.

C. The SCI Division field office will complete Form SC-16, Notice for Hold for 

Reexamination, to notify the applicant that the product exceeds the FDA guidelines for 

aflatoxin.

D. If desired, the applicant will send a letter on company letterhead and signed by a company 

official to S&T, TSB to request retesting of the product. This letter must include:

1. Appeal for retesting with the lot broken down into sub-lots (normally a sub-lot is a 

pallet);

2. Product name; 

3. Primary container code;
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 14 of 157

4. Case count, and number and size of containers per case (e.g. 480 cases 6/No 10 

cans);

5. Current location(s) of product and amount of product at each site; 

6. Method desired for shipment of samples to laboratory. 

E. The TSB will send an email message or fax to Inspection Operations in Washington, DC 

containing the following information:

1. Applicant's name, location, telephone number, and fax number (if applicable); 

2. Request for sampling on a sub-lot by sub-lot basis, or other sampling plan that is 

acceptable to SCI Division in the event of a claim for indemnification;

3. Product name; 

4. Primary container code;

5. Case count, and number and size of containers per case (e.g. 480 cases 6/No 10 

cans);

6. Current location(s) of product and amount of product at each site; 

and

7. Method of shipment to laboratory 

F. Inspection Operations in Washington, DC will send an email message requesting sampling 

to (based on location) the Eastern, Central, or Western Regional office and also notify the 

Division Director. The message will contain all of the information shown in item 5 on the 

previous page along with any additional instructions that may be necessary. 

G. Each sub-lot must be marked by some means so as to be separately identifiable. This is 

the responsibility of the applicant. However, if the applicant is acting in good faith and 

each pallet is marked the same, one acceptable way to mark the sub-lots is to stamp the 

cases with the USDA "Officially Sampled" stamp with a different lot number for each 

sub-lot. Case stamping procedures may be found in the AIM Inspection Series General 

Procedures Manual. The SCI Division field office will sample the product by sub-lot and 

will mark each sub-lot in a manner that will identify it from all other sub-lots. The field 

office will complete Form SC-637, Laboratory Sample Submittal Sheet, which may be 

found at the following intranet address: 

https://usdagcc.sharepoint.com/sites/ams/AMSFormsCatalog/Forms/AllItems.aspx to 

accompany the samples to the S&T laboratory. The samples will be clearly marked to 

indicate the sub-lot identification. Samples are shipped at the applicant's expense. The 

field office shall confirm with the plant how they prefer the samples to be shipped. 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 15 of 157

I. The SCI Division field office will bill the applicant for the sampling, stamping (if 

necessary), and travel. 

J. The SCI Division field office will send an email message to Inspection Operations in 

Washington, DC notifying when the samples are to be shipped to the laboratory, with 

copies to (based on location) the Eastern, Central, or Western Regional office, TSB, and 

the laboratory. 

K. When the samples arrive at the laboratory, the laboratory will notify TSB, the SCI 

Division field office, and Inspection Operations in Washington, DC by fax or email.

L. The laboratory will perform aflatoxin analysis in duplicate on each sample, and 

immediately report the analytical results to the SCI Division field office and to TSB by 

telephone, fax or email.

M. The TSB will send a fax or email message to the Inspection Operations in Washington, 

DC containing the applicant's name and the following information for each location: 

1. Product name; 

2. List of aflatoxin results (in ppb), and number of cases for each sub-lot;

3. The statement "Sub-lot No(s). ___________ exceed(s) FDA administrative 

guidelines of 20 ppb aflatoxin";

4. Number of cases (and pounds) that pass; 

5. Number of cases (and pounds) that fail; and 

6. Total number of cases (and pounds). 

N. The S&T aflatoxin laboratory will notify the applicant by telephone or fax of average 

analytical results.

O. The laboratory will prepare the certificate of analyses in the usual manner with the 

following exceptions: 

1. For each lot and each primary container code, all sub-lots meeting FDA guidelines 

will be reported on one certificate.

2. For each lot and each primary container code, all sub-lots failing FDA guidelines 

will be reported on one certificate.

3. In both cases (a. and b.), each sub-lot is listed separately with its corresponding 
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 16 of 157

analytical result.

P. The laboratory will send a copy of each certificate prepared to TSB and the SCI Division 

field office and distribute the remainder of the certificates in the usual manner. The 

laboratory will bill the applicant for the analyses.

Q. The TSB will provide the Inspection Operations in Washington, DC with a photocopy of 

each certificate.

R. Failing product must be destroyed to the satisfaction of SCI Division, or the lot reported to 

FDA, per our Memorandum of Understanding (MOU). 

S. Inspection Operations in Washington, DC will notify the Eastern, Central, or Western 

Regional office and field office that the product must be destroyed, and issue instructions 

for witnessing the destruction of the product by a USDA inspector. The instructions 

should consist of the following: 

1. Notify the applicant that the product is not to be destroyed unless a USDA 

inspector is present. If an inspector is not present at time of destruction, FDA will 

be notified of the sub-lots in violation. 

2. The field office is to notify Inspection Operations in Washington, DC, through 

(based on location) Eastern, Central, or Western Regional office, of how the 

applicant intends to destroy the product. If the method of destruction is acceptable 

to the National office, the field office will be advised. 

3. During the destruction, the USDA inspector will record the following: 

a. Date;

b. Applicant's name and address;

c. Truck identification (truck number or license number) used to transport the 

product; 

d. Name and address of dump site; 

e. Method of destruction; 

f. Lot identification (primary container codes, sub-lot numbers); 

g. Number of cases, size and kind of containers, and number of pounds of 

product; and 

h. Certificate number(s) of aflatoxin analyses certificate(s) covering the 

product. 
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ATTRIBUTES

An attribute may be defined as a characteristic or quality of a thing, a food product in this case. 

As used in statistics, the term “attributes” refers to when a record shows only the number of 

articles conforming and the number of articles not conforming to any specified requirement. 

Attributes standards are directed toward specific quality levels based on predetermined acceptable 

average numbers of defects per hundred units of product. Acceptable quality level (AQL), is 

defined as the average number of defects per hundred units of product in a lot that is acceptable 

for the grade. The emphasis in attribute standards is placed on the lot as a whole instead of the 

individual container or sample unit. The amounts of defects permitted for the various grades 

(specific quality levels) are expressed in terms of numbers of defects per hundred units, geared to 

a specified sample unit’s sizes and acceptable quality levels.

The current U.S. Standards for Sampling Plans are found in the Code of Federal Regulations 

(CFR) Title 7, Chapter 1, Part 43, 43.101, 43.102, 43.103, 43.104, 43.105, and 43.106 which are 

located at the following internet address: https://www.ecfr.gov/cgi-bin/ECFR?page=browse. 

BRIX MEASUREMENT

The term "Brix" technically means the percent by weight of sugar solids in a pure sucrose 

solution. 

Fresh Products 

In fresh fruits it is generally referred to as soluble solids. Use the equipment and procedures in 

the General Market Manual for any fresh commodity that does not have an established procedure 

in the U.S. standards or inspection instructions. Products such as cantaloupes, table grapes, and 

watermelons have specific guidelines and instructions in determining soluble solids in their 

respective commodity inspection instructions. 

Processed Products 

In canned fruits, fruit juice, and similar products Brix is commonly used as a convenient term to 

express the percent by weight of all soluble solids in solutions. The solutions are generally not 

pure sucrose but contain sweeteners or mixtures of two or more types of sweeteners, and small 

amounts of other substances. 

The instruments generally used for Brix measurement are Brix hydrometers and refractometers. 

These instruments are affected not only by the sugars present in a product but also by such 

substances as fruit acids, pectins, and minerals. Regardless of the composition of the solution, the 

Brix reading expresses the soluble solids content of the solution in terms of a Brix value 

corresponding to a pure sucrose solution of the same specific gravity. 
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The final Brix measurement of liquid packing media in canned fruit and similar products depends 

largely on four factors: 

 1. The soluble solids of the in-going fresh products. 

 2. The Brix of the in-going liquid medium.

 3. The proportion of fresh product to packing medium, and 

4. The extent to which the finished product (fresh product and liquid medium) has 

equalized.

Canned fruits are usually packed in a liquid medium, which may range from a water pack (no 

added sweetener), to a packing medium of natural juice, to a syrup of relatively high sugar 

content. The statement shown on the inspection certificate to indicate syrup density may be 

"syrup designation" or "Brix measurement." The appropriate statement to use when certifying 

canned fruits in a liquid media is described in the AIM Inspection Series Certification Manual. 

Liquid Packing Medium 

Most liquid packing media fall into one of the following categories or syrup designations: 

1. Artificially sweetened. 

2. In fruit juice(s). 

3. In fruit juice(s) and water. 

4. In water. 

5. Slightly sweetened water, or extra light syrup, or slightly sweetened fruit juice(s) 

and water, or slightly sweetened fruit juice(s).

6. Light syrup, or lightly sweetened fruit juice(s) and water, or lightly sweetened fruit 

juice(s).

7. Heavy syrup, or heavily sweetened fruit juice(s) and water, or heavily sweetened 

fruit juice(s).

8. Extra heavy syrup, or extra heavily sweetened fruit juice(s) and water, or extra 

heavily sweetened fruit juice(s).

The Brix measurement for each designation varies with the product. Inspectors must refer 

to the applicable U.S. Standards for Grades, buyer's specification, and Division 

instructions for special certification criteria to determine the actual requirements. 

Inspection and Certification Criteria

When certifying the liquid medium, inspectors shall consider certain Food and Drug 

Administration (FDA) mandatory requirements or U.S. Standards for Grades recommendations as 

to the following: 
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A. The Brix of a liquid packing medium is not evaluated as a factor of quality when applying 

the United States Standards for Grades. However, these standards do provide 

recommended or mandatory FDA syrup designations based on specified Brix 

measurements.

B. Brix determination for syrup designation is a definite requirement in many specifications 

for canned fruits. The requirement may also be incorporated in a procurement document 

or buyer's specification. 

C. Drained weights are sometimes predicated upon specified syrup designations. For 

example, the recommended drained weight for Canned Red Tart Pitted Cherries packed in 

a sweetened medium differs from those packed in water.

D. The Brix measurement(s) shown on the certificate of quality and condition is the soluble 

solids determination made at the time of final examination. This must be after the 

equalization of the natural sugars in the fruit and the in-going liquid medium. See 

Equalization – Terminology. 

Acceptance Criteria

Use the following guide to allow for a reasonable variation in syrup densities and at the same time 

be within the limits of good commercial practice. A lot will be considered as meeting a required, 

recommended, or declared syrup designation under the following conditions: 

A. The average of the Brix measurements from all the sample units falls within the range for 

the designated syrup; and 

B. No individual reading is below the range of the next lower syrup designation, or above the 

range of the next higher syrup designation. If no lower syrup designation exists, none may 

fall more than 2 degrees Brix below the minimum of the specified designation. 

Preparation of Samples

A. Equalization – Terminology 

To properly evaluate Brix readings, it is important that the product has reached 

equalization with the packing medium. In the case of canned fruits and vegetables packed 

in syrup, complete equalization may require several weeks. However, unless otherwise 

stated in the particular standard or specification, assume that equalization is completed 15 

days after packing. Even though the product and packing media may not have completely 

equalized during this period, the process is sufficiently complete for inspection and 

certification purposes. 

Complete equalization may be accomplished at any time by comminuting the product and 

packing medium using the proper equipment and techniques. This procedure is referred to 

as simulated equalization. It will yield results comparable to natural equalization without 
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requiring a 15 day delay in inspection. 

The two basic categories of products on which Brix is measured: 

1. Naturally equalized products (either by prolonged storage or by the nature of the 

product), 

2. Non-equalized products. 

Samples are to be taken from individual containers only. Composite samples are not to be 

used. 

B. Procedure for Equalized Products 

Mix the sample. Completely liquid products should be stirred while still in the original 

container. Liquid packing media of products such as canned fruits is recovered during or 

after the drained weight step, while the fruit remains on the sieve. The container 

collecting the drained liquid must be free from water and reasonably free from syrup 

adhering from previous samples. Containers used for syrup samples that are borderline, or 

in dispute, shall be cleaned and dried for each reading. Syrup collected in this manner is 

considered well mixed. 

1. Transfer syrup to a standard laboratory glass cylinder and take the Brix hydrometer 

reading. Smaller containers with sufficient liquid content may be poured directly 

from the can into the cylinder. 

2. Make temperature corrections (if needed).

3. If a refractometer is used, follow procedure as outlined in Section G of this 

subsection. 

C. Procedure for Non-Equalized Products 

Simulated equalization replicates the natural equalization of soluble solids in the fruit or 

vegetable ingredient and the packing media. The entire contents of the canned product are 

comminuted into a homogeneous liquid state, and the degrees Brix of this slurry is 

determined by refractometer. The degrees Brix found is considered equivalent to the Brix 

obtained by hydrometer on the liquid packing media of equalized product. 

The following equipment is required to perform this procedure: 

1. Blender or other similar machine with bowl size adequate to accommodate the 

contents of can sizes from a 2 1⁄2 to a No. 10 can. 

2. Refractometer, water cooled, and equipped with thermometer and suitable light 

source.
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3. Temperature corrections chart for refractometer Brix scale (included on page 31 of 

this instruction). 

4. Soft applicator such as plastic spatula or rod tipped with rubber policeman. 

5. Filtering equipment:

a. Funnel, 

b. Test tube,

c. Filter paper. 

Note: Nylon cloth or similar material may be used in lieu of filter paper 

provided comparable results can be obtained. 

Perform the procedure as follows: 

a. Pour entire contents of container into blender bowl. Whole, unpitted fruit 

should be carefully pitted, and pitted product should be checked for pits 

before comminuting. Transfer all of the fruit and liquid to the bowl. 

b. Comminute the sample until homogeneous. This process should take from 

one to two minutes. Check efficiency of blending by occasionally pouring 

a sample onto a clean, dry pan and visually examining for lumps of fruit or 

vegetable flesh. Further mixing is needed if lumps are present. (It is 

usually not possible to completely liquefy maraschino cherries used in fruit 

cocktail and fruit mixes; however, final results are not adversely affected). 

Avoid excessive mixing since it overheats the sample. The inspector will 

come to know the correct mixing times with experience. 

An alternative method for overcoming any small container problem is the 

use of double-dilution with an equal part by weight of distilled water, 

comminuting and multiplying the result by 2. 

c. Filter if necessary, discarding the first few drops. Avoid evaporation by 

covering the sample if not performing the reading immediately.

d. Apply about two drops of sample to the refractometer prisms.

e. Take the reading, make temperature correction if needed, and record 

results.

D. Selection of Brix Measuring Instrument 
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The following selections are recommended but not mandatory. A refractometer may be 

used in lieu of a Hydrometer if equivalent results may be obtained. 

Use Hydrometer for

1. Naturally equalized canned fruit and canned vegetables (such as sweet potatoes in 

syrup) consisting of separate units in a liquid packing medium (including water 

and dietetic packs).

2. Canned, chilled and frozen single-strength fruit juices.

3. Frozen fruits (in-going syrups only). 

4. Special products (such as pickles, pickle relish, molasses and table syrups) as 

specified in standards or specifications and instructions. 

Use Refractometer for

1. Non-equalized canned fruits and canned vegetables (such as sweet potatoes in 

syrup) consisting of separate units in a liquid packing medium, including water and 

dietetic pack - after undergoing simulated equalization. 

2. Canned fruit products such as purees, pulps, butters, jams, preserves and jellies. 

3. Canned and frozen fruit juices other than single-strength.

4. Naturally equalized canned fruit and canned vegetables consisting of separate units 

in a liquid packing medium, where individual containers contain insufficient liquid 

medium to measure by hydrometer.

5. Frozen fruits.

6. Special products, such as honey, as specified in standards, specifications, or 

instructions. 

E. Measurement Techniques

The Brix hydrometer or spindle is a glass instrument consisting of a hollow bulb which 

causes the hydrometer to float. Below this bulb is a section filled with shot which causes 

the instrument to float in an upright position. Above the bulb is a graduated stem from 

which the readings are taken. The extent to which the stem extends above the surface of 

the liquid depends upon the specific gravity of the liquid being tested. 

The instrument is similar to any specific gravity hydrometer indicating degrees of liquid 

density. However, the graduations on the stem of this instrument are expressed in degrees 
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Brix and indicate the percentage of soluble solids in terms of sucrose equivalent. If the 

Brix hydrometer is immersed in a solution composed entirely of sucrose and water, the 

reading at proper temperature is exactly the percentage by weight of pure dry sugar 

(sucrose) in the solution. The degrees Brix is easy to determine, is a convenient 

measurement of the specific gravity in terms of the Brix scale, and reflects the total 

soluble solids in solution. 

The hydrometer most often used in laboratories has a 10 degree range for each spindle 

with graduations in 1

/10 degrees. Most SCI Division laboratories are equipped with 

instruments to cover at least the range from 5 degrees to 40 degrees Brix. 

F. Hydrometer Procedure

The Brix hydrometer should be checked periodically for accuracy. Please see the 

calibration of equipment section of this Manual for instructions. 

Hydrometer usage:

1. Pour the liquid to be examined into a standard glass laboratory cylinder 

(approximately 1 1⁄4 inches inside diameter, 10 to 12 inches tall). Completely fill 

the cylinder, and allow to over flow slightly so as to float off any foam or bubbles. 

2. Remove sufficient liquid from the cylinder to allow the hydrometer to float at a 

level of liquid slightly below the top of the cylinder. This is easy to gauge with a 

little experience. Slowly lower the clean, dry hydrometer into the liquid until it is 

very near floating position. Release spindle with a slight spinning motion. If it is 

dropped into the syrup, it will sink too far and when it rises some of the syrup will 

adhere to the stem. The weight of this adhering syrup will cause the hydrometer to 

float at a lower position than it should. Air bubbles in the syrup will also cause the 

hydrometer to float at an incorrect level.

3. Observe the reading on the stem after allowing the hydrometer to come completely 

to rest. The hydrometer should not touch the side of the glass cylinder. The eye 

should be on a level with the surface of the liquid. Where the liquid touches the 

stem, it rises a short distance to form a meniscus. The correct reading is taken at 

the true liquid level, not at the top of the meniscus. The meniscus layer is usually 

thin and the graduation marks can be seen through it. However, with very dark 

colored syrups it may be necessary to make a slight allowance for the meniscus 

factor. 
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4. Record the temperature of the syrup, and refer to the Brix hydrometer temperature 

correction chart for any appropriate correction. The chart is self-explanatory, but 

note that the correction factor varies according to the specific gravity of the liquid 

as well as with the temperature. The correction factor is taken from the column 

nearest the degree Brix found. For example, if the hydrometer indicates a reading 

of 23.5 degrees Brix, the correction factor is taken from the vertical column headed 

25 degrees Brix. 

5. The Brix hydrometer is a very delicate and fragile instrument. It must be handled 

with care to avoid breakage and should be thoroughly cleaned and dried 

immediately after each use. Store it in an adequately cushioned container to 

protect it from damage.

G. Refractometer Procedure

The refractometer is an instrument that optically measures the density of a liquid. Light 

passes through the sample and is deflected in relation to the density of the sample. The 

instrument is calibrated in terms of refractive index and usually contains a scale in terms 

of degrees Brix. 

A common type of refractometer consists of two prisms between which a portion of the 

test sample is placed. A mirror will reflect light through the prisms and test sample. A 

telescopic tube with cross-hairs is superimposed on the field of vision, correlating to a 

scale calibrated in terms of refractive index, degrees Brix, or both. There is also a 

compensator to correct for the chromatic dispersion of light, and a thermometer in the 

water circulating system. There may be some variation depending on the make and model 

of the individual instrument. Become familiar with your refractometer by studying its 

manual of instructions. Many small, hand-type refractometers are not sufficiently accurate 

for laboratory purposes, but may be used to estimate the soluble solids content of fresh 

fruit. 
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The refractometer should be checked for accuracy before use. This should be on a 

daily basis when in constant use, such as during in-plant inspections. The method 

of determining the instrument's accuracy of calibration will be specified in the 

refractometer manual. Please see the equipment section of this manual for 

calibration instructions. 

Refractometer usage:

1. Apply one or two drops (amount may vary; be guided by your equipment manual) 

of the sample (filtered when necessary) to the lower prism. Be careful not to 

scratch the soft refractometer prisms in the process. Avoid using product that is 

too hot or too cold, as this could also damage the prisms.

2. Close and lock the prism chamber. 

3. Apply the light source and view the shadow through the telescope, keeping the eye 

in the center of the eyepiece. Align the shadow edge (which should be sharp) 

exactly with the intersection of the cross-hairs. 
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An indistinct shadow edge may be caused by: 

a. Insufficient or excessive sample on prisms.

b. Unfiltered sample of purees and slurries.

c. Improper chromatic dispersion adjustment indicated by a blue or red tinge 

in the shadow edge.

d. Insufficient or excessive light directed on the prisms.

e. Improper closing of prisms (too rapid closure of prisms, or prisms not 

locked securely).

f. Light stop that controls the amount of light transmitted to the prisms 

(present on some instruments) is not fully closed. 

4. Read the degrees Brix from the Brix scale. 

Caution: Incorrect readings may be caused by too much sample on the prism (causing the 

liquid to flow around onto the backside of a prism), or by water on the prism from 

incomplete drying from the previous sample. 

5. Note the temperature indicated by the thermometer and make appropriate 

temperature correction.

Temperature greatly influences the Brix reading, and it is essential that the reading 

be corrected to the instrument's standard temperature (usually 20 degrees C/68 

degrees F). This correction is made with a chart similar to the one developed for 

the Brix hydrometer shown at the end of this section. Temperature of the prisms 

should remain as close to standard temperature as practical by adjusting of the flow 

of water through the cooling system. 

6. The refractometer must be kept clean and in proper working order at all times. 
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Clean and dry the prisms with soft, lint free tissues immediately after each reading. 

The prisms are soft and scratch easily; never touch them with hard objects such as 

spoons or glass rods. Place a small piece of soft paper or tissue between them 

when the instrument is not in use, and protect with a cover. Refer to the 

instruction manual for any specific storage or handling procedures. 

Refractometers standardized at 20 degrees C are preferred by the Division. When 

sample temperatures are above or below the temperature at which the instrument is 

calibrated, corrections are based on the standard temperature of the instrument. 

Temperature correction charts included in this instruction are only for instruments 

standardized at 20 degrees C. 

H. Reporting Results 

After adjusting the reading for temperature variation, report results of Brix readings to the 

closest 1/10 or 0.1 degree, or to the appropriate degree per the grading instructions. 

Corrections for the presence of fruit acids, minerals, and similar ingredients are not made 

unless specified in the standard or specification. 

I. Percent Juice Declaration

FDA has declared that the use of standard minimum Brix levels will promote consistency 

in calculating the percentage of juice. Effective May 8, 1994, the FDA established 

minimum Brix levels for fruit and vegetable juices. To declare a fruit or vegetable juice 

prepared from concentrate to be 100 percent juice, the reconstituted juice must meet the 

minimum Brix level indicated in the table. If the Brix reading of a reconstituted juice is 

less than FDA’s minimum required Brix, the product is not considered to be 100 percent 

juice. The processor must calculate the exact percentage of juice and declare the proper 

percentage of juice on the retail label.

Products packed in bulk containers are exempt from FDA’s percent juice declaration 

requirement. 
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FDA Established Minimum Brix Levels

Juice 100 Percent Juice 1/ Juice 100 Percent Juice 1/

Acerola 6.0 Guava 7.7

Apple 11.5 Honeydew melon 9.6

Apricot 11.7 Kiwi 15.4

Banana 22.0 Lemon 4.5 2/

Blackberry 10.0 Lime 4.5 2/

Blueberry 10.0 Loganberry 10.5

Boysenberry 10.0 Mango 13.0

Cantaloupe Melon 9.6 Nectarine 11.8

Carambola 7.8 Orange 11.8 3/

Carrot 8.0 Papaya 11.5

Casaba Melon 7.5 Passion Fruit 14.0

Cashew (Caju) 12.0 Peach 10.5

Celery 3.1 Pear 12.0

Cherry, dark, sweet 20.0 Pineapple 12.8

Cherry, red, sour 14.0 Plum 14.3

Crabapple 15.4 Pomegranate 16.0

Cranberry 7.5 Prune 18.5

Currant (Black) 11.0 Quince 13.3

Currant (Red) 10.5 Raspberry (Black) 11.1

Date 18.5 Raspberry (Red) 9.2

Dewberry 10.0 Rhubarb 5.7

Elderberry 11.0 Strawberry 8.0

Fig 18.2 Tangerine 11.8 3/

Gooseberry 8.3 Tomato 5.0

Grape 16.0 Watermelon 7.8

Grapefruit 10.0 3/ Youngberry 10.0

Guanabana (soursop) 16.0

1/ Indicates Brix value unless other value specified.

2/ Indicates anhydrous citrus acid percent by weight.

3/ Brix values determined by refractometers for citrus juices may be corrected for citric acid.

Note: The Brix levels shown in the above table do not apply to juices that are directly 

extracted from a fruit or vegetable (i.e. not concentrated or reconstituted). Such 

products are considered to be 100 percent juice and will be declared as 100 percent 

juice.

Example: To meet U.S. Grade A, the U.S. Standards for Grades of Frozen Concentrated 

Sweetened Grape Juice require that the reconstituted juice have a Brix of 13.0 
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degrees with a minimum of 50 percent of the solids coming from grape 

concentrate. Even with 100 percent grape solids, the 13.0 degrees Brix does not 

meet the FDA minimum Brix requirement of 16.0 degrees. In this case, the 

processor must declare the actual percent juice on the label. The in-plant inspector 

shall calculate the percentage of juice in the batch and verify that there is no 

discrepancy from the amount declared on the label. 

Note: Since FDA has established a minimum Brix level, no deviants are allowed. 

When a juice or juice beverage product fails the required reconstituted Brix, or fails to 

show the percent juice or the correct percent of juice on the label, document the score 

sheet accordingly, and flag the certificate under the grade statement. See the AIM 

Inspection Series, Certification Manual for examples.

When the product label bears an approved USDA identification mark and the product fails 

FDA’s minimum Brix requirement, the lot will be placed on hold and may not be shipped. 

This would also apply to lots labeled incorrectly for percentage of juice. The processor 

has the option to rework the product to meet the Brix requirement; or use a label that states 

the proper percentage of juice.

Processors should contact the FDA (http://www.fda.gov/), if they have any questions 

regarding percentage juice labeling or nutritional facts that relate to the Nutritional 

Labeling Education Act (NLEA) regulations. 

Identity labeling of food in packaged form, FDA regulations 21 CFR 101.30, 

https://www.ecfr.gov/cgi-bin/ECFR?page=browse, 

Percentage Juice Declaration, and 21 CFR 102.33, https://www.ecfr.gov/cgibin/ECFR?page=browse, 

Information on beverages that contain fruit and vegetable juice are available at the 

selection of internet addresses listed above. 
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TEMPERATURE CORRECTIONS FOR OBTAINING BRIX FROM REFRACTOMETER READINGS

Temp.

Degrees

C.

Degrees Brix

0 5 10 15 20 25 30 40 50 60 70

Subtract from Brix Reading

10 .50 .54 .58 .61 .64 .66 .68 .72 .74 .76 .79

11 .46 .49 .53 .55 .58 .60 .62 .65 .67 .69 .71

12 .42 .45 .48 .50 .52 .54 .56 .58 .60 .61 .63

13 .37 .40 .42 .44 .46 .48 .49 .51 .53 .54 .55

14 .33 .35 .37 .39 .40 .41 .42 .44 .45 .46 .48

15 .27 .29 .31 .33 .34 .34 .35 .37 .38 .39 .40

16 .22 .24 .25 .26 .27 .28 .28 .30 .30 .31 .32

17 .17 .18 .19 .20 .21 .21 .21 .22 .23 .23 .24

18 .12 .13 .13 .14 .14 .14 .14 .15 .15 .16 .16

19 .06 .06 .06 .07 .07 .07 .07 .08 .08 .08 .08

Add to Degrees Brix Reading

21 .06 .07 .07 .07 .07 .08 .08 .08 .08 .08 .08

22 .13 .13 .14 .14 .15 .15 .15 .15 .16 .16 .16

23 .19 .20 .21 .22 .22 .23 .23 .23 .24 .24 .24

24 .26 .27 .28 .29 .30 .30 .31 .31 .31 .32 .32

25 .33 .35 .36 .37 .38 .38 .39 .40 .40 .40 .40

26 .40 .42 .43 .44 .45 .46 .47 .48 .48 .48 .48

27 .48 .50 .52 .53 .54 .55 .55 .56 .56 .56 .56

28 .56 .57 .60 .61 .62 .63 .63 .64 .64 .64 .64

29 .64 .66 .68 .69 .71 .72 .72 .73 .73 .73 .73

30 .72 .74 .77 .78 .79 .80 .80 .81 .81 .81 .81
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SUCROSE CONVERSION TABLE

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

 per Gallon

1.3330 0.0 1.00000 8.322 0.000

1.3331 0.0 1.00039 8.325 0.008

1.3333 0.2 1.00078 8.328 0.017

1.3334 0.3 1.00117 8.331 0.025

1.3336 0.4 1.00156 8.335 0.033

1.3337 0.5 1.00194 8.338 0.042

1.3339 0.6 1.00233 8.341 0.050

1.3340 0.7 1.00272 8.344 0.059

1.3341 0.8 1.00312 8.348 0.067

1.3343 0.9 1.00351 8.351 0.075

1.3344 1.0 1.00390 8.354 0.084

1.3346 1.1 1.00429 8.357 0.092

1.3347 1.2 1.00468 8.361 0.100

1.3349 1.3 1.00507 8.364 0.109

1.3350 1.4 1.00546 8.367 0.117

1.3352 1.5 1.00585 8.370 0.126

1.3353 1.6 1.00624 8.374 0.134

1.3354 1.7 1.00663 8.377 0.142

1.3356 1.8 1.00702 8.380 0.151

1.3357 1.9 1.00741 8.383 0.159

1.3359 2.0 1.00780 8.387 0.168

1.3360 2.1 1.00819 8.390 0.176

1.3362 2.2 1.00859 8.393 0.185

1.3363 2.3 1.00898 8.396 0.193

1.3365 2.4 1.00937 8.400 0.202

1.3366 2.5 1.00977 8.403 0.210

1.3368 2.6 1.01016 8.406 0.219

1.3369 2.7 1.01055 8.409 0.227

1.3370 2.8 1.01094 8.413 0.236

1.3372 2.9 1.01134 8.416 0.244

1.3373 3.0 1.01173 8.419 0.252

1.3375 3.1 1.01213 8.423 0.261
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Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3376 3.2 1.01252 8.426 0.270

1.3377 3.3 1.01292 8.429 0.278

1.3379 3.4 1.01331 8.432 0.287

1.3380 3.5 1.01371 8.436 0.295

1.3382 3.6 1.01410 8.439 0.304

1.3383 3.7 1.01450 8.442 0.312

1.3385 3.8 1.01490 8.446 0.321

1.3386 3.9 1.01529 8.449 0.329

1.3388 4.0 1.01569 8.452 0.338

1.3389 4.1 1.01609 8.456 0.347

1.3391 4.2 1.01649 8.459 0.355

1.3392 4.3 1.01688 8.462 0.364

1.3394 4.4 1.01728 8.465 0.372

1.3395 4.5 1.01768 8.469 0.381

1.3397 4.6 1.01808 8.472 0.390

1.3398 4.7 1.01848 8.475 0.398

1.3400 4.8 1.01888 8.479 0.407

1.3401 4.9 1.01928 8.482 0.416

1.3402 5.0 1.01968 8.485 0.424

1.3404 5.1 1.02008 8.489 0.433

1.3405 5.2 1.02048 8.492 0.441

1.3407 5.3 1.02088 8.495 0.450

1.3408 5.4 1.02128 8.499 0.459

1.3410 5.5 1.02168 8.502 0.468

1.3411 5.6 1.02208 8.505 0.476

1.3413 5.7 1.02248 8.509 0.485

1.3414 5.8 1.02289 8.512 0.494

1.3416 5.9 1.02329 8.515 0.502

1.3417 6.0 1.02369 8.519 0.511

1.3419 6.1 1.02409 8.522 0.520

1.3420 6.2 1.02450 8.526 0.529

1.3422 6.3 1.02490 8.529 0.537
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 33 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3423 6.4 1.02530 8.532 0.546

1.3425 6.5 1.02571 8.536 0.555

1.3426 6.6 1.02611 8.539 0.564

1.3428 6.7 1.02652 8.542 0.572

1.3429 6.8 1.02692 8.546 0.581

1.3431 6.9 1.02733 8.549 0.590

1.3432 7.0 1.02773 8.552 0.599

1.3434 7.1 1.02814 8.556 0.607

1.3435 7.2 1.02854 8.559 0.616

1.3437 7.3 1.02895 8.563 0.625

1.3438 7.4 1.02936 8.566 0.634

1.3440 7.5 1.02976 8.569 0.643

1.3441 7.6 1.03017 8.573 0.652

1.3443 7.7 1.03058 8.576 0.660

1.3444 7.8 1.03098 8.580 0.669

1.3446 7.9 1.03139 8.583 0.678

1.3447 8.0 1.03180 8.586 0.687

1.3449 8.1 1.03221 8.590 0.696

1.3450 8.2 1.03262 8.593 0.705

1.3452 8.3 1.03303 8.597 0.714

1.3454 8.4 1.03344 8.600 0.722

1.3455 8.5 1.03385 8.603 0.731

1.3457 8.6 1.03426 8.607 0.740

1.3459 8.7 1.03467 8.610 0.749

1.3460 8.8 1.03508 8.614 0.758

1.3461 8.9 1.03549 8.617 0.767

1.3463 9.0 1.03590 8.620 0.776

1.3464 9.1 1.03631 8.624 0.785

1.3466 9.2 1.03672 8.627 0.794

1.3467 9.3 1.03713 8.631 0.803

1.3469 9.4 1.03755 8.634 0.812

1.3470 9.5 1.03796 8.638 0.821
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 34 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3472 9.6 1.03837 8.641 0.830

1.3473 9.7 1.03879 8.644 0.838

1.3475 9.8 1.03920 8.648 0.848

1.3476 9.9 1.03961 8.651 0.856

1.3478 10.0 1.04003 8.655 0.866

1.3480 10.1 1.04044 8.658 0.874

1.3481 10.2 1.04086 8.662 0.884

1.3483 10.3 1.04127 8.665 0.892

1.3484 10.4 1.04169 8.669 0.902

1.3486 10.5 1.04210 8.672 0.911

1.3487 10.6 1.04252 8.675 0.920

1.3489 10.7 1.04293 8.679 0.929

1.3490 10.8 1.04335 8.682 0.938

1.3492 10.9 1.04377 8.686 0.947

1.3493 11.0 1.04418 8.689 0.956

1.3495 11.1 1.04460 8.693 0.965

1.3497 11.2 1.04502 8.696 0.974

1.3498 11.3 1.04544 8.700 0.983

1.3500 11.4 1.04585 8.703 0.992

1.3501 11.5 1.04627 8.707 1.001

1.3503 11.6 1.04669 8.710 1.010

1.3504 11.7 1.04711 8.714 1.020

1.3506 11.8 1.04753 8.717 1.029

1.3507 11.9 1.04795 8.721 1.038

1.3509 12.0 1.04837 8.724 1.047

1.3511 12.1 1.04879 8.728 1.056

1.3512 12.2 1.04921 8.731 1.065

1.3514 12.3 1.04963 8.735 1.074

1.3515 12.4 1.05005 8.738 1.084

1.3517 12.5 1.05047 8.742 1.093

1.3518 12.6 1.05090 8.745 1.102

1.3520 12.7 1.05132 8.749 1.111
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 35 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3522 12.8 1.05174 8.752 1.120

1.3523 12.9 1.05216 8.756 1.130

1.3525 13.0 1.05259 8.759 1.139

1.3626 13.1 1.05301 8.763 1.148

1.3528 13.2 1.05343 8.766 1.157

1.3529 13.3 1.05386 8.770 1.166

1.3531 13.4 1.05428 8.773 1.176

1.3533 13.5 1.05470 8.777 1.185

1.3534 13.6 1.05513 8.781 1.194

1.3536 13.7 1.05556 8.784 1.203

1.3537 13.8 1.05598 8.788 1.213

1.3539 13.9 1.05641 8.791 1.222

1.3541 14.0 1.05683 8.795 1.231

1.3542 14.1 1.05726 8.798 1.241

1.3544 14.2 1.05769 8.802 1.250

1.3545 14.3 1.05811 8.805 1.259

1.3547 14.4 1.05854 8.809 1.268

1.3548 14.5 1.05897 8.812 1.278

1.3550 14.6 1.05940 8.816 1.287

1.3552 14.7 1.05982 8.820 1.297

1.3553 14.8 1.06025 8.823 1.306

1.3555 14.9 1.06068 8.827 1.315

1.3556 15.0 1.06111 8.830 1.325

1.3558 15.1 1.06154 8.834 1.334

1.3560 15.2 1.06197 8.837 1.343

1.3561 15.3 1.06240 8.841 1.353

1.3563 15.4 1.06283 8.845 1.362

1.3564 15.5 1.06326 8.848 1.371

1.3566 15.6 1.06369 8.852 1.381

1.3567 15.7 1.06412 8.855 1.390

1.3569 15.8 1.06455 8.859 1.400

1.3571 15.9 1.06499 8.863 1.409
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 36 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3573 16.0 1.06542 8.866 1.419

1.3574 16.1 1.06585 8.870 1.428

1.3576 16.2 1.06629 8.873 1.437

1.3577 16.3 1.06672 8.877 1.447

1.3579 16.4 1.06715 8.881 1.456

1.3581 16.5 1.06759 8.884 1.466

1.3582 16.6 1.06802 8.888 1.475

1.3584 16.7 1.06845 8.891 1.485

1.3586 16.8 1.06889 8.895 1.494

1.3587 16.9 1.06933 8.899 1.504

1.3589 17.0 1.06976 8.902 1.513

1.3591 17.1 1.07020 8.906 1.523

1.3592 17.2 1.07063 8.909 1.532

1.3594 17.3 1.07107 8.913 1.542

1.3595 17.4 1.07151 8.917 1.552

1.3597 17.5 1.07194 8.920 1.561

1.3598 17.6 1.07238 8.924 1.571

1.3600 17.7 1.07282 8.928 1.580

1.3602 17.8 1.07325 8.931 1.590

1.3603 17.9 1.07369 8.935 1.599

1.3605 18.0 1.07413 8.939 1.609

1.3607 18.1 1.07457 8.942 1.619

1.3608 18.2 1.07501 8.946 1.628

1.3610 18.3 1.07545 8.950 1.638

1.3612 18.4 1.07589 8.953 1.647

1.3613 18.5 1.07633 8.957 1.657

1.3615 18.6 1.07677 8.961 1.667

1.3617 18.7 1.07721 8.964 1.676

1.3618 18.8 1.07765 8.968 1.686

1.3620 18.9 1.07809 8.972 1.696

1.3621 19.0 1.07853 8.975 1.705

1.3623 19.1 1.07898 8.979 1.715
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 37 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3625 19.2 1.07942 8.983 1.725

1.3626 19.3 1.07986 8.986 1.734

1.3628 19.4 1.08030 8.990 1.744

1.3630 19.5 1.08075 8.994 1.754

1.3631 19.6 1.08119 8.997 1.763

1.3633 19.7 1.08164 9.001 1.773

1.3635 19.8 1.08208 9.005 1.783

1.3636 19.9 1.08252 9.008 1.792

1.3638 20.0 1.08297 9.012 1.802

1.3640 20.1 1.08342 9.016 1.812

1.3641 20.2 1.08386 9.020 1.822

1.3643 20.3 1.08431 9.023 1.832

1.3645 20.4 1.08475 9.027 1.842

1.3646 20.5 1.08520 9.031 1.851

1.3648 20.6 1.08565 9.034 1.861

1.3650 20.7 1.08609 9.038 1.871

1.3651 20.8 1.08654 9.042 1.881

1.3653 20.9 1.08699 9.046 1.891

1.3655 21.0 1.08744 9.049 1.900

1.3656 21.1 1.08789 9.053 1.910

1.3658 21.2 1.08834 9.057 1.920

1.3660 21.3 1.08879 9.061 1.930

1.3661 21.4 1.08923 9.064 1.940

1.3663 21.5 1.08968 9.068 1.950

1.3665 21.6 1.09013 9.072 1.960

1.3667 21.7 1.09058 9.076 1.969

1.3668 21.8 1.09103 9.079 1.979

1.3670 21.9 1.09149 9.083 1.989

1.3672 22.0 1.09194 9.087 1.999

1.3673 22.1 1.09239 9.091 2.009

1.3675 22.2 1.09284 9.094 2.019

1.3677 22.3 1.09329 9.098 2.029
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 38 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3678 22.4 1.09375 9.102 2.039

1.3680 22.5 1.09420 9.106 2.049

1.3682 22.6 1.09465 9.109 2.059

1.3683 22.7 1.09511 9.113 2.069

1.3685 22.8 1.09556 9.117 2.079

1.3687 22.9 1.09602 9.121 2.089

1.3688 23.0 1.09647 9.125 2.099

1.3690 23.1 1.09693 9.128 2.109

1.3692 23.2 1.09738 9.132 2.119

1.3694 23.3 1.09784 9.136 2.129

1.3695 23.4 1.09829 9.140 2.139

1.3697 23.5 1.09875 9.143 2.149

1.3699 23.6 1.09921 9.147 2.159

1.3700 23.7 1.09966 9.151 2.169

1.3702 23.8 1.10012 9.155 2.179

1.3704 23.9 1.10058 9.159 2.189

1.3706 24.0 1.10104 9.163 2.199

1.3707 24.1 1.10149 9.166 2.209

1.3709 24.2 1.10195 9.170 2.219

1.3711 24.3 1.10241 9.174 2.229

1.3712 24.4 1.10287 9.178 2.239

1.3714 24.5 1.10333 9.182 2.250

1.3716 24.6 1.10370 9.185 2.260

1.3718 24.7 1.10425 9.189 2.270

1.3719 24.8 1.10471 9.193 2.280

1.3721 24.9 1.10517 9.197 2.290

1.3723 25.0 1.10564 9.201 2.300

1.3724 25.1 1.10610 9.205 2.310

1.3726 25.2 1.01656 9.208 2.320

1.3728 25.3 1.10702 9.212 2.331

1.3729 25.4 1.10748 9.216 2.341

1.3731 25.5 1.10795 9.220 2.351
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 39 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3733 25.6 1.10841 9.224 2.361

1.3735 25.7 1.10887 9.228 2.372

1.3736 25.8 1.10934 9.232 2.382

1.3738 25.9 1.10980 9.235 2.392

1.3740 26.0 1.11027 9.239 2.402

1.3741 26.1 1.11073 9.243 2.412

1.3743 26.2 1.11120 9.247 2.423

1.3745 26.3 1.11166 9.251 2.433

1.3747 26.4 1.11213 9.255 2.443

1.3748 26.5 1.11260 9.259 2.454

1.3750 26.6 1.11306 9.263 2.464

1.3752 26.7 1.11353 9.266 2.474

1.3753 26.8 1.11400 9.270 2.484

1.3755 26.9 1.11447 9.274 2.495

1.3757 27.0 1.11493 9.278 2.505

1.3759 27.1 1.11540 9.282 2.515

1.3761 27.2 1.11587 9.286 2.526

1.3762 27.3 1.11634 9.290 2.536

1.3764 27.4 1.11681 9.294 2.547

1.3766 27.5 1.11728 9.298 2.557

1.3768 27.6 1.11775 9.302 2.567

1.3769 27.7 1.11822 9.305 2.578

1.3771 27.8 1.11869 9.309 2.588

1.3773 27.9 1.11916 9.313 2.598

1.3775 28.0 1.11963 9.317 2.609

1.3777 28.1 1.12010 9.321 2.619

1.3778 28.2 1.12058 9.325 2.630

1.3780 28.3 1.12105 9.329 2.640

1.3782 28.4 1.12152 9.333 2.651

1.3784 28.5 1.12199 9.337 2.661

1.3785 28.6 1.12247 9.341 2.672

1.3787 28.7 1.12294 9.345 2.682
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 40 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3789 28.8 1.12342 9.349 2.693

1.3791 28.9 1.12389 9.353 2.702

1.3792 29.0 1.12436 9.357 2.714

1.3794 29.1 1.12484 9.361 2.724

1.3796 29.2 1.12532 9.365 2.735

1.3798 29.3 1.12579 9.369 2.745

1.3800 29.4 1.12627 9.372 2.755

1.3801 29.5 1.12674 9.376 2.766

1.3803 29.6 1.12722 9.380 2.776

1.3805 29.7 1.12770 9.384 2.787

1.3807 29.8 1.12817 9.388 2.798

1.3809 29.9 1.12865 9.392 2.808

1.3810 30.0 1.12913 9.396 2.819

1.3812 30.1 1.12961 9.400 2.829

1.3814 30.2 1.13009 9.404 2.840

1.3816 30.3 1.13057 9.408 2.851

1.3818 30.4 1.13105 9.412 2.861

1.3820 30.5 1.13153 9.416 2.872

1.3821 30.6 1.13201 9.420 2.883

1.3823 30.7 1.13249 9.424 2.893

1.3825 30.8 1.13297 9.428 2.904

1.3827 30.9 1.13345 9.432 2.914

1.3829 31.0 1.13394 9.436 2.925

1.3830 31.1 1.13442 9.440 2.936

1.3832 31.2 1.13490 9.444 2.947

1.3834 31.3 1.13538 9.448 2.957

1.3836 31.4 1.13587 9.452 2.968

1.3838 31.5 1.13635 9.456 2.979

1.3839 31.6 1.13683 9.460 2.990

1.3841 31.7 1.13732 9.464 3.000

1.3843 31.8 1.13780 9.468 3.011

1.3845 31.9 1.13829 9.472 3.022
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 41 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3847 32.0 1.13877 9.477 3.033

1.3848 32.1 1.13926 9.481 3.043

1.3850 32.2 1.13974 9.485 3.054

1.3852 32.3 1.14023 9.489 3.065

1.3854 32.4 1.14072 9.493 3.076

1.3856 32.5 1.14120 9.497 3.087

1.3858 32.6 1.14169 9.501 3.097

1.3860 32.7 1.14218 9.505 3.108

1.3861 32.8 1.14267 9.509 3.119

1.3863 32.9 1.14316 9.513 3.130

1.3865 33.0 1.14364 9.517 3.141

1.3867 33.1 1.14413 9.521 3.151

1.3869 33.2 1.14462 9.525 3.162

1.3871 33.3 1.14511 9.529 3.173

1.3872 33.4 1.14560 9.533 3.184

1.3874 33.5 1.14609 9.537 3.195

1.3876 33.6 1.14658 9.541 3.206

1.3878 33.7 1.14708 9.546 3.217

1.3879 33.8 1.14757 9.550 3.228

1.3881 33.9 1.14806 9.554 3.239

1.3883 34.0 1.14855 9.558 3.250

1.3885 34.1 1.14904 9.562 3.261

1.3887 34.2 1.14954 9.566 3.272

1.3889 34.3 1.15003 9.570 3.283

1.3891 34.4 1.15052 9.574 3.293

1.3893 34.5 1.15102 9.578 3.304

1.3894 34.6 1.15151 9.583 3.316

1.3896 34.7 1.15201 9.587 3.327

1.3898 34.8 1.15250 9.591 3.338

1.3900 34.9 1.15300 9.595 3.349

1.3902 35.0 1.15350 9.599 3.360

1.3904 35.1 1.15399 9.603 3.371
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 42 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3906 35.2 1.15449 9.607 3.382

1.3908 35.3 1.15498 9.611 3.393

1.3909 35.4 1.15548 9.616 3.404

1.3911 35.5 1.15598 9.620 3.415

1.3913 35.6 1.15648 9.624 3.426

1.3915 35.7 1.15698 9.628 3.437

1.3916 35.8 1.15747 9.632 3.448

1.3918 35.9 1.15797 9.636 3.459

1.3920 36.0 1.15847 9.640 3.470

1.3922 36.1 1.15897 9.645 3.482

1.3924 36.2 1.15947 9.649 3.493

1.3926 36.3 1.15997 9.653 3.504

1.3928 36.4 1.16047 9.657 3.515

1.3930 36.5 1.16098 9.661 3.526

1.3931 36.6 1.16148 9.665 3.537

1.3933 36.7 1.16198 9.670 3.549

1.3935 36.8 1.16248 9.674 3.560

1.3937 36.9 1.16298 9.678 3.571

1.3939 37.0 1.16349 9.682 3.582

1.3941 37.1 1.16399 9.686 3.594

1.3943 37.2 1.16449 9.691 3.605

1.3945 37.3 1.16500 9.695 3.616

1.3947 37.4 1.16550 9.699 3.627

1.3949 37.5 1.16601 9.703 3.639

1.3950 37.6 1.16652 9.707 3.650

1.3952 37.7 1.16702 9.712 3.661

1.3954 37.8 1.16752 9.716 3.673

1.3956 37.9 1.16803 9.720 3.684

1.3958 38.0 1.16853 9.724 3.695

1.3960 38.1 1.16904 9.728 3.706

1.3962 38.2 1.16955 9.733 3.718

1.3964 38.3 1.17006 9.737 3.729
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 43 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.3966 38.4 1.17056 9.741 3.741

1.3968 38.5 1.17107 9.745 3.752

1.3970 38.6 1.17158 9.749 3.763

1.3972 38.7 1.17209 9.754 3.775

1.3794 38.8 1.17260 9.758 3.786

1.3976 38.9 1.17311 9.762 3.797

1.3978 39.0 1.17362 9.766 3.809

1.3980 39.1 1.17413 9.771 3.820

1.3982 39.2 1.17464 9.775 3.832

1.3984 39.3 1.17515 9.779 3.843

1.3986 39.4 1.17566 9.783 3.855

1.3988 39.5 1.17618 9.788 3.866

1.3989 39.6 1.17669 9.792 3.878

1.3991 39.7 1.17720 9.796 3.889

1.3993 39.8 1.17772 9.801 3.901

1.3995 39.9 1.17823 9.805 3.912

1.3997 40.0 1.17874 9.809 3.924

1.3999 40.1 1.17926 9.813 3.935

1.4001 40.2 1.17977 9.818 3.947

1.4003 40.3 1.18029 9.822 3.958

1.4005 40.4 1.18080 9.826 3.970

1.4007 40.5 1.18132 9.831 3.982

1.4008 40.6 1.18183 9.835 3.993

1.4010 40.7 1.18235 9.839 4.004

1.4012 40.8 1.18287 9.843 4.016

1.4014 40.9 1.18339 9.848 4.028

1.4016 41.0 1.18390 9.852 4.039

1.4018 41.1 1.18442 9.856 4.051

1.4020 41.2 1.18494 9.861 4.063

1.4022 41.3 1.18546 9.865 4.074

1.4024 41.4 1.18598 9.869 4.086

1.4026 41.5 1.18650 9.874 4.098
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 44 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4028 41.6 1.18702 9.878 4.109

1.4030 41.7 1.18754 9.882 4.121

1.4032 41.8 1.18806 9.887 4.133

1.4034 41.9 1.18858 9.891 4.144

1.4036 42.0 1.18910 9.895 4.156

1.4038 42.1 1.18962 9.900 4.167

1.4040 42.2 1.19014 9.904 4.179

1.4042 42.3 1.19062 9.908 4.191

1.4044 42.4 1.19119 9.913 4.203

1.4046 42.5 1.19171 9.917 4.215

1.4048 42.6 1.19224 9.921 4.226

1.4050 42.7 1.19276 9.926 4.238

1.4052 42.8 1.19329 9.930 4.250

1.4054 42.9 1.19381 9.935 4.262

1.4056 43.0 1.19434 9.939 4.274

1.4058 43.1 1.19486 9.943 4.285

1.4060 43.2 1.19539 9.948 4.298

1.4062 43.3 1.19591 9.952 4.309

1.4064 43.4 1.19644 9.956 4.321

1.4066 43.5 1.19697 9.961 4.333

1.4068 43.6 1.19749 9.965 4.345

1.4070 43.7 1.19802 9.970 4.357

1.4072 43.8 1.19855 9.974 4.369

1.4074 43.9 1.19908 9.978 4.380

1.4076 44.0 1.19961 9.983 4.393

1.4078 44.1 1.20013 9.987 4.404

1.4080 44.2 1.20066 9.992 4.416

1.4082 44.3 1.20119 9.996 4.428

1.4084 44.4 1.20172 10.000 4.440

1.4086 44.5 1.20226 10.005 4.452

1.4088 44.6 1.20279 10.009 4.464

1.4090 44.7 1.20332 10.014 4.476
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 45 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4092 44 .8 1.20385 10.018 4.488

1.4094 44.9 1.20438 10.022 4.500

1.4096 45.0 1.20491 10.027 4.512

1.4098 45.1 1.20545 10.031 4.524

1.4100 45.2 1.20598 10.036 4.536

1.4102 45 .3 1.20651 10.040 4.548

1.4104 45.4 1.20705 10.045 4.560

1.4107 45.5 1.20758 10.049 4.572

1.4109 45.6 1.20812 10.054 4.585

1.4111 45.7 1.20865 10.058 4.597

1.4113 45.8 1.20919 10.063 4.609

1.4115 45.9 1.20972 10.067 4.621

1.4117 46.0 1.21026 10.071 4.633

1.4119 46.1 1.21080 10.076 4.645

1.4121 46.2 1.21133 10.080 4.657

1.4123 46.3 1.21187 10.085 4.669

1.4125 46.4 1.21241 10.089 4.681

1.4127 46.5 1.21295 10.094 4.694

1.4129 46.6 1.21349 10.098 4.706

1.4131 46.7 1.21402 10.103 4.718

1.4133 46.8 1.21456 10.107 4.730

1.4135 46.9 1.21510 10.112 4.743

1.4137 47.0 1.21564 10.116 4.755

1.4139 47.1 1.21618 10.121 4.767

1.4141 47.2 1.21673 10.125 4.779

1.4143 47.3 1.21727 10.130 4.791

1.4145 47.4 1.21781 10.134 4.804

1.4148 47.5 1.21835 10.139 4.816

1.4150 47.6 1.21889 10.143 4.828

1.4152 47.7 1.21943 10.148 4.841

1.4154 47.8 1.21998 10.152 4.853

1.4156 47.9 1.22052 10.157 4.865
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 46 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4158 48.0 1.22106 10.161 4.877

1.4160 48.1 1.22161 10.166 4.890

1.4162 48.2 1.22215 10.170 4.902

1.4164 48.3 1.22270 10.175 4.915

1.4166 48.4 1.22324 10.179 4.927

1.4169 48.5 1.22379 10.184 4.939

1.4171 48.6 1.22434 10.189 4.952

1.4173 48.7 1.22488 10.193 4.964

1.4175 48.8 1.22543 10.198 4.977

1.4177 48.9 1.22598 10.202 4.989

1.4179 49.0 1.22652 10.207 5.001

1.4181 49.1 1.22707 10.211 5.014

1.4183 49.2 1.22762 10.216 5.026

1.4185 49.3 1.22817 10.220 5.039

1.4187 49.4 1.22872 10.225 5.051

1.4190 49.5 1.22927 10.230 5.064

1.4192 49.6 1.22982 10.234 5.076

1.4194 49.7 1.23037 10.239 5.089

1.4196 49.8 1.23092 10.243 5.101

1.4199 49.9 1.23147 10.248 5.114

1.4201 50.0 1.23202 10.252 5.126

1.4203 50.1 1.23257 10.257 5.139

1.4205 50.2 1.23313 10.262 5.152

1.4207 50.3 1.23368 10.266 5.164

1.4209 50.4 1.23423 10.271 5.177

1.4212 50.5 1.23478 10.275 5.189

1.4214 50.6 1.23534 10.280 5.202

1.4216 50.7 1.23589 10.285 5.214

1.4218 50.8 1.23645 10.289 5.227

1.4220 50.9 1.23700 10.294 5.240

1.4222 51.0 1.23756 10.299 5.252

1.4224 51.1 1.23811 10 .303 5.265
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 47 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4226 51.2 1.23867 10.308 5.278

1.4228 51.3 1.23922 10.312 5.290

1.4230 51.4 1.23978 10.317 5.303

1.4233 51.5 1.24034 10.322 5.316

1.4235 51.6 1.24089 10.326 5.328

1.4237 51.7 1.24145 10.331 5.341

1.4239 51.8 1.24201 10.336 5.354

1.4241 51.9 1.24257 10.340 5.366

1.4243 52.0 1.24313 10.345 5.379

1.4245 52.1 1.24369 10.350 5.392

1.4248 52.2 1.24425 10.354 5.405

1.4250 52.3 1.24481 10.359 5.418

1.4252 52.4 1.24537 10.364 5.431

1.4254 52.5 1.24593 10.368 5.443

1.4256 52.6 1.24649 10.373 5.456

1.4258 52.7 1.24705 10.378 5.469

1.4260 52.8 1.24761 10.382 5.482

1.4262 52.9 1.24818 10.387 5.495

1.4265 53.0 1.24874 10.392 5.508

1.4267 53.1 1.24930 10.396 5.520

1.4269 53.2 1.24987 10.401 5.533

1.4271 53.3 1.25043 10.406 5.546

1.4273 53.4 1.25099 10.410 5.559

1.4275 53.5 1.25156 10.415 5.572

1.4278 53.6 1.25212 10.420 5.585

1.4280 53.7 1.25269 10.425 5.598

1.4282 53.8 1.25325 10.429 5.611

1.4284 53.9 1.25382 10.434 5.624

1.4286 54.0 1.25439 10.439 5.637

1.4288 54.1 1.25495 10.443 5.650

1.4291 54.2 1.25552 10.448 5.663

1.4293 54.3 1.25609 10.453 5.676
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 48 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4295 54.4 1.25666 10.458 5.689

1.4297 54.5 1.25723 10.462 5.702

1.4299 54.6 1.25780 10.467 5.715

1.4301 54.7 1.25836 10.472 5.728

1.4304 54.8 1.25893 10.476 5.741

1.4306 54.9 1.25950 10.481 5.754

1.4308 55.0 1.26007 10.486 5.767

1.4310 55.1 1.26064 10.491 5.781

1.4312 55.2 1.26122 10.495 5.793

1.4315 55.3 1.26179 10.500 5.807

1.4317 55.4 1.26236 10.505 5.820

1.4319 55.5 1.26293 10.510 5.833

1.4321 55.6 1.26350 10.515 5.846

1.4323 55.7 1.26408 10.519 5.859

1.4326 55.8 1.26465 10.524 5.872

1.4328 55.9 1.26522 10.529 5.886

1.4330 56.0 1.26580 10.534 5.899

1.4332 56.1 1.26637 10.538 5.912

1.4334 56.2 1.26695 10.543 5.925

1.4337 56.3 1.26752 10.548 5.939

1.4339 56.4 1.26810 10.553 5.952

1.4341 56.5 1.26868 10.558 5.965

1.4343 56.6 1.26925 10.562 5.978

1.4345 56.7 1.26983 10.567 5.991

1.4348 56.8 1.27041 10.572 6.005

1.4350 56.9 1.27098 10.577 6.018

1.4352 57.0 1.27156 10.581 6.031

1.4354 57.1 1.27214 10.586 6.045

1.4356 57.2 1.27272 10.591 6.058

1.4359 57.3 1.27330 10.596 6.072

1.4361 57.4 1.27388 10.601 6.085

1.4363 57.5 1.27446 10.606 6.098
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 49 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4365 57 .6 1.27504 10.610 6.111

1.4368 57.7 1.27562 10.615 6.125

1.4370 57.8 1.27620 10.620 6.138

1.4372 57.9 1.27678 10.625 6.152

1.4374 58.0 1.27736 10.630 6.165

1.4376 58.1 1.27794 10.635 6.179

1.4379 58.2 1.27853 10.640 6.192

1.4381 58.3 1.27911 10.644 6.205

1.4383 58.4 1.27969 10.649 6.219

1.4385 58.5 1.28028 10.654 6.233

1.4388 58.6 1.28086 10.659 6.246

1.4390 58.7 1.28145 10.664 6.260

1.4392 58.8 1.28203 10.669 6.273

1.4394 58.9 1.28262 10.674 6.287

1.4397 59.0 1.28320 10.678 6.300

1.4399 59.1 1.28379 10.683 6.314

1.4401 59.2 1.28437 10.688 6.327

1.4403 59.3 1.28497 10.693 6.341

1.4406 59.4 1.28555 10.698 6.355

1.4408 59.5 1.28614 10.703 6.368

1.4410 59.6 1.28672 10.708 6.382

1.4412 59.7 1.28731 10.713 6.396

1.4415 59.8 1.28789 10.718 6.409

1.4417 59 .9 1.28849 10.722 6.422

1.4419 60.0 1.28908 10.727 6.436

1.4422 60.1 1.28966 10.732 6.450

1.4424 60.2 1.29025 10.737 6.464

1.4426 60.3 1.29084 10.742 6.477

1.4428 60.4 1.29143 10.747 6.491

1.4431 60.5 1.29023 10.752 6.505

1.4433 60.6 1.29262 10.757 6.519

1.4435 60.7 1.29321 10.762 6.533
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 50 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4437 60.8 1.29380 10.767 6.546

1.4440 60.9 1.29439 10.772 6.560

1.4442 61.0 1.29498 10.777 6.574

1.4444 61.1 1.29559 10.781 6.587

1.4447 61.2 1.29618 10.786 6.601

1.4449 61.3 1.29677 10.791 6.615

1.4451 61.4 1.29736 10.796 6.629

1.4453 61.5 1.29796 10.801 6.643

1.4456 61.6 1.29855 10.806 6.656

1.4458 61.7 1.29915 10.811 6.670

1.4460 61.8 1.29975 10.816 6.684

1.4463 61.9 1.30034 10.821 6.698

1.4465 62.0 1.30093 10.826 6.712

1.4467 62.1 1.30153 10.831 6.726

1.4470 62.2 1.30212 10.836 6.740

1.4472 62.3 1.30273 10.841 6.754

1.4474 62.4 1.30334 10.846 6.768

1.4476 62.5 1.30393 10.851 6.782

1.4479 62.6 1.30453 10.856 6.796

1.4481 62.7 1.30513 10.861 6.810

1.4483 62.8 1.30573 10.866 6.824

1.4486 62.9 1.30633 10.871 6.838

1.4488 63.0 1.30694 10.876 6.852

1.4490 63.1 1.30754 10.881 6.866

1.4493 63.2 1.30815 10.886 6.880

1.4495 63.3 1.30875 10.891 6.894

1.4497 63.4 1.30936 10.896 6.908

1.4500 63.5 1.30994 10.901 6.922

1.4502 63.6 1.31055 10.906 6.936

1.4504 63.7 1.31117 10.911 6.950

1.4507 63.8 1.31177 10.916 6.964

1.4509 63.9 1.31237 10.921 6.978
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 51 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4511 64.0 1.31297 10.926 6.993

1.4514 64.1 1.31359 10.931 7.007

1.4516 64.2 1.31418 10.936 7.021

1.4518 64.3 1.31479 10.941 7.035

1.4521 64.4 1.31540 10.946 7.049

1.4523 64.5 1.31600 10.951 7.063

1.4525 64.6 1.31661 10.956 7.078

1.4528 64.7 1.31723 10.961 7.092

1.4530 64.8 1.31784 10.967 7.107

1.4532 64.9 1.31845 10.972 7.121

1.4535 65.0 1.31905 10.977 7.135

1.4537 65.1 1.31966 10.982 7.149

1.4539 65.2 1.32028 10.987 7.164

1.4542 65.3 1.32089 10.992 7.178

1.4544 65.4 1.32150 10.997 7.192

1.4546 65.5 1.32210 11.002 7.206

1.4549 65.6 1.32271 11.007 7.221

1.4551 65.7 1.32332 11.012 7.235

1.4553 65.8 1.32393 11.017 7.249

1.4556 65.9 1.32455 11.022 7.263

1.4558 66.0 1.32516 11.027 7.278

1.4561 66.1 1.32577 11.033 7.293

1.4563 66.2 1.32638 11.038 7.307

1.4565 66.3 1.32699 11.043 7.322

1.4568 66.4 1.32759 11.048 7.336

1.4570 66.5 1.32820 11.053 7.350

1.4572 66.6 1.32884 11.058 7.365

1.4575 66.7 1.32945 11.063 7.379

1.4577 66.8 1.33007 11.068 7.393

1.4580 66.9 1.33068 11.073 7.408

1.4582 67.0 1.33129 11.079 7.423

1.4584 67.1 1.33192 11.084 7.437
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 52 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4587 67.2 1.33254 11.089 7.452

1.4589 67.3 1.33315 11.094 7.466

1.4591 67.4 1.33377 11.099 7.481

1.4594 67.5 1.33438 11.104 7.495

1.4596 67.6 1.33500 11.110 7.510

1.4599 67.7 1.33562 11.115 7.525

1.4601 67.8 1.33625 11.120 7.539

1.4603 67.9 1.33686 11.125 7.554

1.4606 68.0 1.33748 11.130 7.568

1.4608 68.1 1.33810 11.135 7.583

1.4611 68.2 1.33872 11.140 7.597

1.4613 68.3 1.33935 11.146 7.613

1.4615 68.4 1.33997 11.151 7.627

1.4618 68.5 1.34059 11.156 7.642

1.4620 68.6 1.34121 11.161 7.656

1.4623 68.7 1.34183 11.166 7.671

1.4625 68.8 1.34245 11.172 7.686

1.4628 68.9 1.34309 11.177 7.701

1.4630 69.0 1.34371 11.182 7.716

1.4632 69.1 1.34433 11.187 7.730

1.4635 69.2 1.34495 11.192 7.745

1.4637 69.3 1.34558 11.198 7.760

1.4640 69.4 1.34621 11.203 7.775

1.4642 69.5 1.34684 11.208 7.790

1.4644 69.6 1.34746 11.213 7.804

1.4647 69.7 1.34809 11.218 7.819

1.4649 69.8 1.34871 11.224 7.834

1.4652 69.9 1.34934 11.229 7.849

1.4654 70.0 1.34997 11.234 7.864

1.4657 70.1 1.35060 11.239 7.879

1.4659 70.2 1.35123 11.245 7.894

1.4661 70.3 1.35186 11.250 7.909
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 53 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4664 70.4 1.35248 11.255 7.924

1.4666 70.5 1.35311 11.260 7.938

1.4669 70.6 1.35375 11.265 7.953

1.4671 70.7 1.35438 11.271 7.969

1.4674 70.8 1.35501 11.276 7.983

1.4676 70.9 1.35564 11.281 7.998

1.4679 71.0 1.35627 11.286 8.013

1.4681 71.1 1.35691 11.292 8.029

1.4684 71.2 1.35754 11.297 8.043

1.4686 71.3 1.35817 11.302 8.058

1.4688 71.4 1.35881 11.308 8.074

1.4691 71.5 1.35944 11.313 8.089

1.4693 71.6 1.36008 11.318 8.104

1.4696 71.7 1.36072 11.323 8.119

1.4698 71.8 1.36135 11.329 8.134

1.4701 71.9 1.36198 11.334 8.149

1.4703 72.0 1.36261 11.339 8.164

1.4706 72.1 1.36324 11.345 8.180

1.4708 72.2 1.36389 11.350 8.195

1.4711 72.3 1.36452 11.355 8.210

1.4713 72.4 1.36516 11.360 8.225

1.4716 72.5 1.36579 11.366 8.240

1.4718 72.6 1.36643 11.371 8.255

1.4721 72.7 1.36707 11.376 8.270

1.4723 72.8 1.36771 11.382 8.286

1.4725 72.9 1.36836 11.387 8.301

1.4728 73.0 1.36900 11.392 8.316

1.4730 73.1 1.36964 11.398 8.332

1.4733 73.2 1.37028 11.403 8.347

1.4735 73.3 1.37092 11.408 8.362

1.4738 73.4 1.37156 11.414 8.378

1.4740 73.5 1.37220 11.419 8.393
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 54 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4743 73.6 1.37283 11.424 8.408

1.4745 73.7 1.37347 11.430 8.424

1.4748 73.8 1.37411 11.435 8.439

1.4750 73.9 1.37476 11.440 8.454

1.4753 74.0 1.37541 11.446 8.470

1.4756 74.1 1.37605 11.451 8.485

1.4758 74.2 1.37669 11.456 8.500

1.4760 74.3 1.37733 11.462 8.516

1.4763 74.4 1.37798 11.467 8.531

1.4765 74.5 1.37864 11.473 8.547

1.4768 74.6 1.37928 11.478 8.563

1.4770 74.7 1.37993 11.483 8.578

1.4773 74.8 1.38057 11.489 8.594

1.4776 74.9 1.38122 11.494 8.609

1.4778 75.0 1.38187 11.499 8.624

1.4781 75.1 1.38252 11.505 8.640

1.4783 75.2 1.38316 11.510 8.656

1.4786 75.3 1.38381 11.516 8.672

1.4788 75.4 1.38445 11.521 8.687

1.4791 75.5 1.38510 11.526 8.703

1.4793 75.6 1.38575 11.532 8.718

1.4796 75.7 1.38640 11.537 8.734

1.4798 75.8 1.38705 11.543 8.750

1.4801 75.9 1.38770 11.548 8.765

1.4803 76.0 1.38835 11.554 8.781

1.4806 76.1 1.38902 11.559 8.796

1.4808 76.2 1.38967 11.564 8.812

1.4811 76.3 1.39032 11.570 8.828

1.4814 76.4 1.39097 11.575 8.843

1.4816 76.5 1.39162 11.581 8.859

1.4819 76.6 1.39228 11.586 8.875

1.4821 76.7 1.39293 11.592 8.891
SCI Division Inspection Series Technical Procedures Manual

Effective Date: June 2020 Page 55 of 157

Refractive Index at 

20 Degrees C 

Percent Sucrose or 

Degrees Brix

Apparent 

Specific Gravity 

@ 20/20 Degrees C

Weight/Gal. in air 

at 20 Degrees C 

Pounds Solids 

per Gallon

1.4824 76.8 1.39358 11.597 8.906

1.4826 76.9 1.39423 11.602 8.922

1.4829 77.0 1.39489 11.608 8.938

1.4831 77.1 1.39554 11.613 8.954

1.4834 77.2 1.39619 11.619 8.970

1.4836 77.3 1.39685 11.624 8.985

1.4839 77.4 1.39750 11.630 9.002

1.4841 77.5 1.39816 11.635 9.017

1.4844 77.6 1.39882 11.641 9.033

1.4847 77.7 1.39949 11.646 9.049

1.4849 77.8 1.40014 11.652 9.065

1.4852 77.9 1.40080 11.657 9.081

1.4854 78.0 1.40146 11.663 9.097

1.4857 78.1 1.40211 11.668 9.113

1.4860 78.2 1.40277 11.673 9.128

1.4862 78.3 1.40344 11.679 9.145

1.4865 78.4 1.40409 11.684 9.160

1.4867 78.5 1.40475 11.690 9.177

1.4870 78.6 1.40541 11.695 9.192

1.4873 78.7 1.40607 11.701 9.209

1.4875 78.8 1.40674 11.706 9.224

1.4878 78.9 1.40740 11.712 9.241

1.4880 79.0 1.40806 11.717 9.256

1.4883 79.1 1.40872 11.723 9.273

1.4886 79.2 1.40938 11.728 9.289

1.4888 79.3 1.41005 11.734 9.305

1.4891 79.4 1.41072 11.740 9.322

1.4893 79.5 1.41138 11.745 9.337

1.4896 79.6 1.41204 11.751 9.354

1.4899 79.7 1.41270 11.756 9.370

1.4901 79.8 1.41337 11.762 9.386

1.4904 79.9 1.41404 11.767 9.402

1.4906 80.0 1.41471 11.773 9.418
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CALIBRATION OF EQUIPMENT

Accurate results from equipment rely on standardized procedures and properly calibrated 

equipment. Equipment such as refractometers or thermometers should be calibrated before use 

instead of set intervals if usage is infrequent. Calibration logs have been established to record 

these readings and to document the calibration process. The calibration logs noted below are 

guides and may be used for photocopying and maintaining as documentation of inspectors' 

results. 

Any equipment that cannot be calibrated within specified guidelines should be "tagged" and 

removed from usage. Equipment without serial numbers or some other means of identification 

should be labeled with a property decal. 

Thermometers

Fresh Products 

Refer to the Thermometer sections of the General Market Manual for guidelines regarding proper 

use and calibration of thermometers used in the inspection of fresh products. 

Processed Products 

Thermometers used for checking the temperatures of food products should be tested every week, 

or as often as each inspection if any potential abuse has ensued (such as carton penetration). The 

test is made by immersing the thermometer in an ice and water bath. 

Fill an appropriate size beaker with ice and then water. Stir for 2 minutes and then immerse the 

thermometer for 2 minutes in the center of the mixture. Do not permit the thermometer bulb to 

rest against the side of the container. The thermometer may be held vertically by fitting it through 

a perforated piece of cardboard positioned across the top of the beaker. The thermometer should 

read within 1° + of +32°F (0°C). Record results on the Thermometer Checks log in 

APPENDIX I. 

There may be a need to test the thermometer at other temperatures. For calibration at 

temperatures from 0° to -5°F., use a brine mixture consisting of 1 part of salt and 3 parts chipped 

ice. Compare the thermometers being tested with a thermometer that is known to be accurate, i.e. 

traceable to the National Institute of Standards and Technologies (NIST). Insert both 

thermometers into the brine mixture with the stems next to each other. Do not permit either of the 

thermometer bulbs to rest against the side of the container. Wait 2 minutes and compare and 

record readings on the Thermometer Checks log in APPENDIX I. 

Scales

Fresh Products 

Refer to the Scales section of the General Market Manual for guidelines regarding proper use and 
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calibration of scales used in the inspection of fresh products. 

Processed Product 

The scales used for checking net weights and drained weights should be calibrated weekly or 

more often as recommended by the owner’s manual and the results recorded on the appropriate 

log. The scales used for analytical weighing are generally calibrated yearly by a service 

technician. 

A. Gram Scales

a. Complete value readings with an NIST class weight, preferably 10 g and 100 g 

weights. Record results to the 0.0 g. 

b. Tare scale to zero reading.

c. Add the 10 g weight. 

d. Record reading; adjust as necessary per the owner's manual. Record on the 

Weekly Gram Scale Checks log in APPENDIX II. 

e. Reweigh 10 g if necessary.

f. Add 100 g weight. 

g. Record reading; adjust as necessary per the owner's manual. Record on the 

Weekly Gram Scale Checks log in APPENDIX II. 

h. Reweigh 100 g if necessary. 

i. Return to zero and recheck calibrations if adjustments were made. 

B. Ounce Scales

Follow the above procedures using a NIST class weight, preferably 10-ounce and 80-ounce 

weights. Recording results to the 0.0 ounce. Record on the Weekly Ounce Scale Checks 

log in APPENDIX III. 

Refractometer

Fresh Products 

Refer to the General Market Manual for guidelines regarding general use of a refractometer when 

not specifically covered within an commodity grading manual for fresh product. 
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It is important that the refractometer be properly adjusted before use. Otherwise it will be 

impossible to make an accurate determination of the sugar content. It will be found most convenient 

to adjust the instrument to read zero with distilled water at the temperature at which the test will be 

made. As the temperature changes during the day it will be necessary to readjust the instrument. A 

small supply of distilled water should be kept on hand for this purpose, and precautions taken to 

keep it clean. Tap water should not be used because it frequently contains enough minerals in 

solution to materially affect the reading. Distilled water may be obtained from drug stores, grocery

outlets, chemical supply houses, or laboratories. 

The refractometer must be clean or the accuracy of the reading will be affected. It must be 

thoroughly cleaned (tap water should be used) after each use, as juice allowed to remain and dry on 

the instruments will materially affect the accuracy of the next test made. Care should be taken not 

to scratch the surface of the prism or the hinged plate. 

Processed Products 

The refractometer must be checked daily for compliance by using distilled water or a solution of 

known refractive index and the results recorded on the Refractometer Checks log in 

APPENDIX IV. However, calibration of the refractometer should be done with the test prism (if 

applicable) provided with the instrument. 

A. Equipment 

 1. Test prism

 2. Thin rod with well-rounded end 

 3. Soft lint-free cloth or lens paper

 4. Solvent (isopropyl alcohol) 

 5. Monobromonaphthalene 

 6. Square-headed screwdriver supplied with refractometer

 7. Distilled water

B. Standardizing the Refractometer

The refractometer should be checked for accuracy before use. It must be checked daily 

when in constant use, such as during in-plant inspection and the results recorded on the 

Refractometer Checks log in APPENDIX IV. 

Frequent daily checks may be made with distilled water. The distilled water checks 

supplement less frequent checks with the test prism, and are performed as follows: 

 1. Clean and dry prisms carefully. 

 2. Apply one or two drops of distilled water to prisms. 

 3. Compare observed refractive index and prism temperature with the appropriate 

refractive index for the same temperature (see Refractive Index of Distilled Water 
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chart). If the refractive index reading differs ± 0.0003, repeat steps a and b until a 

total of three readings are obtained. If the refractive index of the last reading still 

differs from the table ± 0.0003, check the refractometer with the standard test 

prism. If the reading still differs plus or minus 0.0003, recalibrate the 

refractometer. 

Caution: Recalibration of the refractometer should be done by an experienced SCI 

Division inspector or plant official. If the plant's quality control 

representative performs the calibration, the USDA inspector should observe 

to assure accuracy.

REFRACTIVE INDEX OF DISTILLED WATER

Temperature

Degrees F Degrees C

Refractometer

Reading

Temperature

Degrees F Degrees C

Refractometer

Reading

59.0 15 1.3334 71.6 22 1.3328

60.8 16 1.3334 73.4 23 1.3327

62.6 17 1.3333 75.2 24 1.3326

64.4 18 1.3332 77.0 25 1.3325

66.2 19 1.3331 78.8 26 1.3324

68.0 20 1.3330 82.4 28 1.3322

69.8 21 1.3329 86.0 30 1.3320

C. Checking for Accuracy

1. If feasible, adjust the refractometer prism temperature as close as possible to the 

standard temperature (20° C). 

2. Clean the lower refractometer prism face with a solvent such as isopropyl alcohol, 

and dry with a soft lint-free cloth or lens paper, making sure no dust fibers adhere to 

the prism face.

 3. Clean the test prism in the same manner as step b.

4. Using a thin rod with a well-rounded end, carefully place a drop of 

monobromonaphthalene on the large polished face of the test prism. The drop 

should not be larger than 1 mm in diameter. 

5. Place the test prism longitudinally in the middle of the lower refractometer prism, 

with its large polished face downward, and small polished face outward toward the 

light source. 
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6. The correct quantity of monobromonaphthalene can be checked by pressing the 

test prism lightly against the refractometer prism face. If any of the solution leaks 

from under any of the test prism edges, the reading will be incorrect, and this 

procedure must be started again from step a. Perform the procedure again if any 

bubbles are trapped under the test prism, as this will also cause an incorrect 

reading. 

7. When the test prism is correctly placed, position the light source so that it is 

directly in line with the small polished face of the test prism. A blue glass filter or 

tissue paper may be held in front of the light source so that the best contrast is 

obtained between the two halves of the field of vision. 

8. Look through the refractometer eyepiece. Locate the shadow edge. Be sure that 

the line does not shift with motion of the light source. Any color fringe on the 

shadow edge can be eliminated by adjusting the chromatic compensator, also 

known as the dispersion correction wheel. This is a rotating drum located on the 

front of the refractometer housing beneath the eyepiece on the Abbe 3L Bausch 

and Lomb type (see illustration on page 25). Refer to the instruction manual if you 

are unsure how to adjust the chromatic compensator of your refractometer. 

9. Reading the scale:

a. On the Bausch and Lomb or Abbe type, the scale is read by depressing the 

switch on the side of the instrument. Release the switch and bring the shadow 

edge to line up at the intersection of the crosshairs as shown below. 
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10. Read the refractive index and compare to the one shown on the test prism. If the 

average of at least three (3) readings differs by more than two units on the fourth 

decimal place, the refractometer must be adjusted.

D. Calibration or Adjustment 

Follow the steps in your refractometer’s instruction manual. 

pH Meter

Most pH meters require daily calibration and standardization to two endpoints (usually pH 4 and 

pH 7, or pH 7 and pH 10) before use. Calibration checks must be documented on at least a 

monthly basis when the pH meter is used infrequently. 

Certified accurate endpoint pH buffer solutions can be purchased from a scientific supply source. 

1. Check the electrodes for freedom from crystals or damage.

2. Follow the owner's manual or instructions provided on the meter. 

3. Check meter in two buffer solutions, and record values on the Daily pH Meter 

Checks log in APPENDIX V. 

Analytical Glassware

Calibration should be performed prior to being placed into service. Glassware can be taped or 

tagged as to calibration. Enter a serial number and date calibrated on the Analytical Glassware 

Checks log in APPENDIX VI. 

Example: 25 ml Pipette/25 ml Burette

1. Tare a 50 ml beaker on a previously calibrated gram scale.
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2. Pipet distilled water up to fill line marked on the pipette.

3. Place pipette over beaker and empty contents into the beaker.

4. Record scale readout. 25 ml = 25 grams. 

5. Results should be within + 0.1 g. If accuracy is less than listed, contact your 

immediate supervisor. Procedures are the same for smaller and larger size 

pipettes and burettes. 

Hydrometer 

A certified accurate hydrometer can be purchased from a scientific supply company. If you have 

a hydrometer(s) with no certification, it can be checked against a certified hydrometer by inserting 

both spindles in the same cylinder of liquid and cross checking the references value. Cross 

checking can also be done with a calibrated refractometer.

Brix hydrometers should be checked for accuracy monthly or before use if usage is infrequent, 

and the results reported on the Hydrometer Checks log in APPENDIX VII. Two methods are 

suggested: 

A. Comparison of the hydrometer reading of a sample of syrup with the reading of another 

hydrometer of known accuracy on the same syrup sample; or,

B. Testing the hydrometer in a specially prepared sucrose solution which contains a known 

percentage by weight, of pure, dry sucrose. For all practical purposes a good grade of dry 

commercial cane or beet sugar will be sufficiently pure for standardization of 

hydrometers. Observe the following guidelines: 

1. Select a value approximately midway on the spindle to be tested. For example, a 

hydrometer in the range of 15 to 20 degrees can be tested in a syrup of 18°. 

2. Prepare a sugar solution of the required density by dissolving a weighed quantity 

of dry, free-running sugar in a weighed quantity of distilled water. 

Example: To prepare 1000 grams of 18° syrup, tare a beaker or other suitable 

receptacle on a gram scale and add exactly 180 grams of dry sugar. Then 

add sufficient water to bring the weight of the mixture (sugar and water) to 

exactly 1000 grams. This solution will give a reading of 18° Brix with an 

accurate hydrometer at the proper temperature. 

Note: 18° Brix is 18% by weight of sugar solids, which is 18 grams per 100 

grams of solution, not 18 grams made up to 100 ml. Do not prepare the 

solution by making up to volume in a volumetric flask. 
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4. Mix the sugar and water well by transferring the contents back and forth between 

two large beakers to assure proper mix. 

5. Cool solution down to about 1 degree below the temperature at which the 

instrument is calibrated.

6. Transfer syrup to a cylinder and equalize to the temperature at which the 

instrument was calibrated. If necessary, immerse in a water bath of the proper 

temperature.

7. When the syrup has reached the proper temperature, immerse the hydrometer and 

observe the reading in accordance with the procedure below. 

8. Take a series of readings by removing the hydrometer and cleaning and drying it 

before each immersion. If the hydrometer reads within 1

/10 of a degree of the 

proper reading, it can be considered sufficiently accurate for our purposes. If the 

error is 2/10 degree, the correction should be recorded, and each reading with this 

instrument adjusted accordingly. If the error in the instrument exceeds 3

/10 degree, 

replace the instrument.

9. For more precise calibration, the instrument can be standardized at more than one 

check point. 

C. Procedure 

1. Pour the liquid into a standard glass laboratory cylinder approximately 1 1⁄4 inches 

inside diameter, 10 to 12 inches tall. Completely fill the cylinder and allow to 

overflow slightly so as to float off any foam or bubbles. 

2. Remove sufficient liquid from the cylinder to allow the hydrometer to float at a 

level of liquid slightly below the top of the cylinder. This is easy to gauge with a 

little experience. 

3. Slowly lower the clean, dry hydrometer into the liquid until it is very near floating

position. Release spindle with a slight spinning motion. If it is dropped into the 

syrup it will sink too far and when it rises, some of the syrup will adhere to the 

stem. The weight of this adhering syrup will cause the hydrometer to float at a 

lower position than it should. Air bubbles in the syrup will also cause the 

hydrometer to float at an incorrect level. 

4. Observe the reading on the stem after allowing the hydrometer to come to a 

complete rest. It must not touch the side of the cylinder. Where the liquid touches 

the stem, it rises a short distance to form a meniscus. Looking at the surface level 

of the liquid, take the reading from the bottom of the meniscus at the true liquid 

level (refer to the Reading Through The Meniscus illustration). 
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5. Record the temperature of the syrup and refer to the Brix hydrometer temperature 

corrections chart below to make any needed correction. Note that the correction 

factor varies according to the specific gravity of the liquid as well as with 

temperature. The correction factor is taken from the column nearest the degrees 

Brix. For example, if the hydrometer indicates a reading of 23.5 degrees Brix, the 

correction factor is taken from the vertical column headed "25 degrees Brix." 
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TEMPERATURE CORRECTIONS -- BRIX HYDROMETERS

(Standardized at 20 degrees C and reported to the nearest 1/10th degree)

Degrees Brix

Temp.

Degrees C 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70

Subtract From Observed Reading

0 .3 .5 .7 .8 .9 1.0 1.1 1.2 1.3 1.4 1.4 1.4 1.4 1.5 1.5

5 .4 .5 .6 .7 .7 .8 .9 .9 1.0 1.0 1.1 1.1 1.1 1.1 1.1

10 .3 .4 .4 .5 .5 .6 .6 .6 .7 .7 .7 .7 .8 .8 .8

11 .3 .4 .4 .4 .5 .5 .6 .6 .6 .6 .7 .7 .7 .7 .7

12 .3 .3 .4 .4 .4 .5 .5 .5 .5 .6 .6 .6 .6 .6 .6

13 .3 .3 .3 .4 .4 .4 .4 .5 .5 .5 .5 .5 .5 .5 .6

14 .2 .3 .3 .3 .3 .4 .4 .4 .4 .4 .4 .5 .5 .5 .5

15 .2 .2 .2 .3 .3 .3 .3 .3 .3 .4 .4 .4 .4 .4 .4

16 .2 .2 .2 .2 .2 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3

17 .1 .1 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2

18 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .2 .2 .2 .2 .2

19 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1

Add to Observed Reading

21 .0 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1 .1

22 .1 .1 .1 .1 .1 .1 .1 .1 .2 .2 .2 .2 .2 .2 .2

23 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2 .2

24 .2 .2 .2 .2 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3 .3

25 .3 .3 .3 .3 .3 .3 .4 .4 .4 .4 .4 .4 .4 .4 .4

26 .3 .3 .4 .4 .4 .4 .4 .4 .5 .5 .5 .5 .5 .5 .5

27 .4 .4 .4 .4 .5 .5 .5 .5 .5 .5 .6 .6 .6 .6 .6

28 .5 .5 .5 .5 .5 .6 .6 .6 .6 .6 .6 .6 .6 .6 .6

29 .5 .6 .6 .6 .6 .6 .7 .7 .7 .7 .7 .7 .7 .7 .7

30 .6 .6 .6 .7 .7 .7 .7 .8 .8 .8 .8 .8 .8 .8 .8

35 1.0 1.0 1.0 1.1 1.1 1.1 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2

40 1.4 1.5 1.5 1.5 1.5 1.6 1.6 1.6 1.6 1.7 1.7 1.7 1.7 1.7 1.7
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Salometer

A salometer is a hydrometer used to measure the concentration of sodium chloride (NaCl) in 

water based on specific gravity. Two types of salometers are used in inspection procedures. A 

description of the two types of salometer follows; instructions for their calibration are provided in 

separate sections as follows.

A. One type of salometer measures the “percent by weight” of NaCl in water at 60 degrees 

Fahrenheit. A saturated solution contains 26.5 percent salt, and the salometer scale ranges 

from 0 to 26.5 percent. This type of salometer is used for brine solutions when testing the 

maturity of peas. For ease of identification in these instructions, this type of salometer 

will be referred to as Type I. 

B. A second type of salometer measures the “percent saturation” of NaCl in water at 60 

degrees Fahrenheit. Readings are recorded as “degrees salometer.” The full scale ranges 

from 0 to 100, but this type of salometer can be purchased in selected ranges. When using 

a salometer with a partial range, the expected readings should be midpoint on the scale, 

and scale divisions should be no greater than 0.2 increments. These salometers may be 

purchased with internal thermometers which are used to apply temperature corrections. 

This type of salometer is called a “combined form” salometer. The “percent saturation” 

salometer is used to measure the amount of NaCl in the brine of canned ripe olives. For 

ease of identification in these instructions, this type of salometer will be referred to as 

Type II. 

C. Instructions for Checking the Calibration of Type I Salometers (used for brining Peas)

1. Visually examine the salometer before each use, and remove any damaged 

salometers from service. Inspect the salometer for:

a. Cracks, chips, etching, or any other signs of damage; 

b. Loose pieces of ballast or other foreign material within the instrument; 

c. Proper alignment of paper scale within the stem, which should be straight 

without any twists; 

d. Alignment of paper scale with scale slippage indicator; and, 

2. Clean and dry the salometer before starting verification procedures. 

3. Prepare a standardized brine solution using the following procedures: 

a. Prepare a 13 percent brine solution by measuring 130 grams of pure, dry 

NaCl (such as kosher salt, not iodized salt) and 870 grams of distilled 

water. 
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b. Mix brine thoroughly. 

c. A 13 percent salt solution is made up by weight, not volume. Do not use a 

volumetric cylinder to make up these solutions. 

4. Verify the accuracy of the salometer using the following procedures: 

a. Test the salometer in a specially prepared brine solution which contains a 

known percentage, by weight, of dry NaCl (see c. above). 

b. Select a hydrometer cylinder appropriate for the size of the salometer:

(1) It must be deep enough that the salometer floats freely at least 25 

mm (1 inch) above the inside bottom; and, 

(2) It must be wide enough that there will be at least 12.5 mm (1⁄2 inch) 

between the inner wall and all surfaces of the immersed salometer. 

The salometer should not touch the sides of the cylinder. 

 

c. The cylinder and salometer must both be clean and dry. 

d. The temperature of the test brine should match the calibration temperature 

of the salometer. Use a water bath if necessary. 

e. Completely fill the cylinder by pouring the brine inside and allowing it to 

overflow slightly so as to float off any foam or bubbles. 

f. Remove sufficient liquid from the cylinder to allow the salometer to float at 

a level of liquid slightly below the top of the cylinder. This is easy to 

gauge with a little experience. Slowly lower the clean, dry salometer into 

the liquid until it is very near floating position. 

g. Release the spindle with a slight spinning motion. If it is dropped into the 

solution, it will sink too far and some of the salt solution will adhere to the 

stem, which can affect the reading. Dropping the salometer may also 

damage it. Any bubbles present will also cause the salometer to read 

incorrectly.

h. Observe the reading on the stem after allowing the salometer to come 

completely to rest. The salometer should not touch the side of the glass 

cylinder. 

i. Read the salometer by observing a point slightly below the plane of the 

liquid surface and raising the line of vision until level with the surface of 

the liquid. Where the liquid touches the stem, it rises a short distance to 

form a meniscus. The reading will be inaccurate if taken at the top of the 
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meniscus rather than at the true liquid level. (See illustration below.) The 

meniscus layer is usually thin and the graduation marks can be seen 

through it. 

j. Record calibration results on the Salometer Calibration log in 

APPENDIX VIII. Include the brine temperature reading.

k. Remove inaccurate salometers from service. 

D. Instructions for Checking the Calibration of Type II Salometers (used for grading Canned 

Ripe Olives)

1. To comply with these instructions, each grading lab will need grading salometers

and a reference standard salometer for calibrating the grading salometers. 

Salometers for grading require a manufacturer’s certificate of conformance. The 

accuracy of all grading salometers will be verified weekly against the reference 

standard salometer, which must have a National Institute of Standards and 

Technology (NIST) traceable certificate of calibration. 

This NIST certificate of calibration references the serial number of the NIST 

Standard used for calibration, and the actual readings taken at three points. The 

NIST traceable reference standard salometer is ONLY used for calibration 

(verifying accuracy) of the grading salometers; it is not to be used for grading. 

Store all salometers with copies of their corresponding certificates.

Contact the Eastern, Central, or Western Regional office for Type II grading 

salometers used to measure the “percent saturation” of NaCl in water at 60 degrees 

Fahrenheit. Type II salometers require daily and weekly calibration checks when 

they are in use. (See paragraphs e and f.) 

2. Visually examine salometer before each use. Inspect the salometer for:

Reading Through The Meniscus
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a. Cracks, chips, etching, or any other signs of damage; 

b. Loose pieces of ballast or other foreign material within the instrument; 

c. Proper alignment of the paper scale within the stem, which should be 

straight without any twists; 

d. Alignment of paper scale with scale slippage indicator. 

Remove any damaged salometers from service. 

3. Clean and dry the salometer before calibrating (verifying accuracy) and before 

each reading. A buildup of salt, oil, or olive particles will affect the accuracy of 

readings.

4. Verify accuracy by testing the grading salometer:

a. Daily - using distilled water; and, 

b. Weekly - by comparing the readings of the grading salometer(s) against the 

readings of the reference standard salometer in the same solution of canned 

ripe olive brine. 

5. Daily Calibration. Verify the accuracy of the grading salometers daily using 

distilled water, and record on the Salometer Checks log in APPENDIX VIII. 

a. Clean and dry both the cylinder and the grading salometer. 

b. Select a (cylinder) appropriate for the size of the salometer.

(1) It must be deep enough that the salometer floats freely at least 25 

mm (1 inch) above the bottom; and 

(2) It must be wide enough that there will be at least 12.5 mm (1⁄2 inch) 

between the inner wall and all surfaces of the immersed salometer. The 

salometer should not touch the sides of the cylinder. 

c. Completely fill the cylinder by pouring distilled water inside and allowing 

it to overflow slightly so as to float off any foam or bubbles. 

d. Remove sufficient liquid from the cylinder to allow the salometer to float at 

a level of liquid slightly below the top of the cylinder. Slowly lower the 

clean, dry grading salometer into the water until it is very near the zero 

reading. 
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e. Release the grading salometer with a slight spinning motion. If it is 

dropped into the solution, it will sink too far and cause the stem to become 

wet, which can affect the reading. It may be damaged if it strikes the 

bottom of the cylinder. Any bubbles present will cause the salometer to 

read incorrectly.

f. Observe the reading on the stem after allowing the grading salometer to 

come completely to rest. The salometer should not touch the side of the 

glass cylinder.

g. Read the grading salometer through the meniscus as for the Type I 

salometer (refer to the Reading Through The Meniscus illustration). The 

reading should be zero. 

h. Apply any corrections for temperature using Appendix H, Grading Manual 

for Canned Ripe Olives. 

i. Record calibration results on Salometer Checks log in APPENDIX VIII. 

Include temperature reading. 

j. Remove inaccurate salometers from service.

k. Repeat steps (1) through (10) to check all grading salometers in use. 

6. Weekly Calibration. A weekly calibration is performed at the beginning of each 

week. It includes all steps for the daily calibration using distilled water, followed 

by a second phase. The second phase is to compare the readings of the grading 

salometer against the NIST certified reference standard salometer in the same

sample of canned ripe olive brine: 

a. The sample of brine should be well-mixed. 

b. Clean and dry the reference standard salometer. The cylinder must be 

either clean and dry, or completely rinsed with a well-mixed sample of the 

brine to be read. 

c. Completely fill the cylinder by pouring the canned ripe olive brine into the 

cylinder and allowing it to overflow slightly so as to float off any foam, 

bubbles, olive particles or olive oil in the sample. 

d. Remove sufficient liquid from the cylinder to allow the grading salometer 

to float at a level of liquid slightly below the top of the cylinder. This is 

easy to gauge with a little experience. Slowly lower the clean, dry grading 

salometer into the brine until it is very near the anticipated reading.
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e. Release the reference salometer with a slight spinning motion. If it is 

dropped into the brine, it will sink too far and some of the brine will adhere 

to the stem and affect the reading. Any bubbles present will also cause the 

salometer to read incorrectly.

f. Observe the reading on the stem after allowing the grading salometer to 

come completely to rest. The salometer should not touch the side of the 

glass cylinder.

g. Read the reference salometer through the meniscus as for the Type I 

salometer (refer to the Reading Through The Meniscus illustration).

h. Record the calibration results, including the temperature reading on the 

salometer calibration log in APPENDIX VIII. Apply corrections for 

temperature using Appendix H, from the Grading Manual for Canned Ripe 

Olives. 

i. Remove the reference salometer from the hydrometer cylinder.

j. Repeat steps (1) through (9) for all grading salometers in use.

Note: Use the same brine for the reference standard salometer and the 

grading salometer(s). Save some of the original brine to add to the 

cylinder if any is lost while taking readings. Reading will be inaccurate 

if brine, oils, or olive particles collect on salometers during grading.

k. The readings for the grading salometer(s) and reference salometer should 

agree.

l. Remove any inaccurate salometers from service.

Colorimeters 

Detailed instructions for calibration should be provided with your model. Recommended 

calibration timetables are as follows. For Hunter models below, light bulb changes are 

recommended at approximately 150 hours of use. 

Record results on the appropriate colorimeter calibration log. 

A. Hunter D45 - weekly zero adjustment. Use log in APPENDIX IX

B. Hunter D45D2 - daily zero adjustment. Use log in APPENDIX X

Modified units require calibration only when the bulb is changed 

Computer controlled units have no manual zero adjustments 
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C. D45D2 - weekly tile check. 

Modified units require calibration only when the bulb is changed. 

Computer controlled units require calibration only when the bulb is changed. 

CONTAINER INFORMATION 

Sizes of metal containers

The following table may be used as a reference for the various can sizes and capacities. Any 

individual container may vary from the figures given in these tables as the result of normal 

variations in manufacture and variations in closure. Capacities will also vary with the profile of 

the ends. The dimensions and capacities given are generally recognized as standard 

measurements.

The practical method for the determination of a fill such as "not less than 90 percent of the 

capacity of the container" is by means of the headspace gauge. The headspace allowance of 10 

percent (or for a 90 percent fill) shown in the Capacity - Sizes of Metal Containers table contained 

in this section, is calculated for the can size. To calculate Headspace for containers other than 

those shown, or for Headspace allowances other than 10%, calculate from the formula given 

below under Headspace. 

The following terms are used in the Capacity-Sizes of Metal Containers table.

Avoirdupois: A system of weights (or mass) based on a pound of sixteen ounces. It is the 

everyday system of weight used in the United States, and will be referred to in these instructions 

in term of the appropriate English system weight, i.e. ounces, pounds, etc. 

Designation: The common name of container. 

Dimensions: The overall measurements, given in terms familiar to the industry. The left-hand 

digit gives the whole inches and the two right-hand digits give the additional fraction expressed in 

sixteenths of an inch. The first set of numbers represents the diameter and the second set of 

numbers represents the height. Example: 211 x 304 means 2 11/16 inches in diameter, 3 4

/16 inches 

in height. 

Water Capacity: The weight of distilled water at 68 degrees F that a sealed container will hold 

when filled to 3/16 inch from the top. Capacity of containers is expressed in ounces. See the 

section titled Procedure to Determine the Water Capacity in section F for instructions. 

Headspace: measured from top of double seam in sixteenths of an inch, calculated as follows: 

Overall height less both seams, times 10%, plus top seam = headspace of 10% 

Example: [(4 11/16 inches minus 6/16 inch) x 10%] + 3/16 inch = 9.9/16 inch, or, 

[(75/16 - 6/16) x (0.10)] = 69/16 x 0.1 = 6.9/16 + 3/16 = 9.9/16 (rounded to 10/16 inch). 
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Cans per Case: Although other packs may be used, most of those listed are typical of the industry 

by representatives of box manufacturers, canners, other interested parties, and by the National 

Institute of Standards and Technology (NIST). 

Capacity - Sizes of Metal Containers

Designation Dimensions Water Capacity 

(Ounces)

Fluid

Measure

(fl. ounces)

Headspace

of 10 Percent

(sixteenths 

of an inch)

Cans

Per Case

5 oz 202 x 214 4.8 4.6 7 12-24-48

6 oz 202 x 308 6 5.8 8 24-48

202 x 314 6.75 6.5 8.6 24

211 x 200 4.9 4.7 5.6 24

No. 211 baby food 211 x 210 6.75 6.5 6.6 48

4 oz mushroom 211 x 212 7.15 6.85 6.8 12-24

8 oz short 211 x 300 7.9 7.6 7.2 24-36-48

72-96

8 oz tall 211 x 304 8.65 8.3 7.6 24-36-48-72

No. 1 picnic 211 x 400 10.9 10.45 8.8 24-48

No. 211 cylinder 211 x 414 13.55 13 10.2 24-36-48

Pint (Olive) 211 x 600 16.96 16.25 12 12-24

4 oz pimiento 300 x 108 4.2 4.05 4.8

7 oz pimiento 300 x 206 7.5 7.2 6.2

12 oz (or 8 oz 

mushroom)

300 x 400 13.55 13 8.8 24

No. 300 300 x 407 15.2 14.6 9.5 24-36-48

300 x 411 16.1 15.5 9.9 48

No. 300 cylinder 300 x 509 19.4 18.6 11.3 24

No. 1 flat 301 x 208 8.2 7.85 6.4 24

No. 1 301 x 400 13.98 13.4 8.8 24

No. 1 tall 301 x 411 16.6 15.95 9.9 24-48

No. 1 square 300 x 308 x 308 17.27 16.6 8 24-48

No. 303 303 x 406 16.85 16.2 9.4 12-24-36

No. 303 303 x 504 20.55 19.75 10.8 24
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No. 303 cylinder 303 x 509 21.85 21 11.3 12-24

No. 2 vacuum 307 x 306 14.7 14.1 7.8 24

No. 2 short 303 x 400 17.75 17.05 8.8 24

No. 2 western 307 x 408 20.2 19.4 9.6 24

No. 2 standard 307 x 409 20.5 19.7 9.7 12-24

Jumbo 307 x 510 25.7 24.7 11.4 12-24

No. 2 cylinder 307 x 512 26.35 25.3 11.6 24

No. 2 tall 307 x 604 28.8 27.65 12.4 12-24

No. 1-1/4 401 x 207.5 14.44 13.87 6.4 24

No. 2-1/2 401 x 411 29.75 28.55 9.9 12-24

No. 2-1/2 square 300x308x604 32.47 31.2 12.4 24

No. 3 vacuum (or squat) 404 x 307 23.85 22.9 7.9 24

No. 3 404 x 414 35.05 33.65 10.2 24

No. 3 cylinder 404 x 700 51.7 49.61 13.6 12

No. 5 502 x 510 59.1 56.75 11.4 12

No. 10 603 x 700 109.45 105.1 13.6 6 

No. 12 603 x 812 138.35 132.85 16.4 4-6 

No. 12 610 x 800 145.7 139.85 15.2 6 

Explanation of Dimensional Food Can Standards 

Metal can sizes used in industry in the U.S.A. are derived from nominal outside dimensions. 

Measurements are made of the empty round can before seaming on the packers' end. 

While such dimensions may be expressed in inches, the custom is to use a conventionalized 

method in which three-digit numbers are used to express each dimension. The first digit indicates 

the number of whole inches in a dimension, and the second and third digits indicate the fractional 

inches as sixteenths of an inch. Therefore: 

303 x 406 means 3-3

/16 x 4-

6

/16 inches 

307 x 512 means 3-7/16 x 5-

12/16 inches 

603 x 700 means 6-3

/16 x 7 inches 
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The first three-digit number describing a round can indicates the diameter measured across the 

outside of the chime on the seamed end. The second three-digit number indicates the overall 

height of the can with one end on. 

Outside dimensions are used to designate the dimensions of oval or round cans. The dimension of 

the opening is stated first, followed by the height. For oval cans, this results in three sets of 

figures, the first two being the long and short axis of the opening. Their interpretation in inches 

and sixteenths of an inch is the same as with round cans. An oval can might have the size given 

as 402 x 304 x 612, which would mean that the oval opening was 4-2

/16 x 3-

4

/16 inches and the 

height was 6-

12/16 inches. 

In the table below the "No. 2 Equivalent" indicates the number of No. 2 cans equal to each of the 

cans designated in the first column. 

Dimensional Food Can Standards

Name Dimensions Total capacity avoir oz. of 

water at 68 degrees F No. 2 Can equivalent

6 oz 202 x 308 6.08 0.295

8 oz Short 211 x 300 7.93 0.386

8 oz Tall 211 x 304 8.68 0.422

No. 1 (Picnic) 211 x 400 10.94 0.532

No. 211 Cylinder 211 x 414 13.56 0.660

No. 300 300 x 407 15.22 0.741

No. 300 Cylinder 300 x 509 19.40 0.945

No. I Tall 301 x 411 16.70 0.813

No. 303 303 x 406 16.88 0.821

No. 303 Cylinder 303 x 509 21.86 1.060

No. 2 Vacuum 307 x 306 14.71 0.716

No. 2 307 x 409 20.55 1.000

Jumbo 307 x 510 25.80 1.2537

No. 2 Cylinder 307 x 512 26.40 1.284

No. 11⁄4 401 x 206 13.81 0.672

No. 21⁄2 401 x 411 29.79 1.450

No. 3 Vacuum 404 x 307 23.90 1.162
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No. 3 Cylinder 404 x 700 51.70 2.515

No. 5 502 x 510 59.10 2.8744

No. 10 603 x 700 109.45 5.325

The capacity of a 16-oz. glass jar is approximately the same as a No. 303 can.

The capacity of a No. 21⁄2 glass jar is approximately the same as a No. 21⁄2 can.

Net contents and fluid measure 

Labeling requirements under the Federal Food, Drug, and Cosmetic Act require certain foods to 

be labeled in terms of weight, and others in terms of liquid measure. In general, the statement is 

in terms of liquid measure if the food is liquid, and in terms of weight if the food is solid, 

semisolid, viscous, or a mixture of solid and liquid. Some exceptions include canned pickles

(expressed in volume) and canned mushrooms (labeled according to the recommended minimum 

drained weight for the container capacity). 

In reporting net contents in containers of products such as juices and other commodities 

customarily labeled and marketed in terms of volume, inspection certificates should record 

contents in fluid measure. 

In determining the net volume (or fluid measure), it is sometimes more rapid and accurate to 

determine the net weight as usual, and convert ounces to fluid ounces by the following formula:

 ounces x 0.9614 

 specific gravity of product

Degrees Brix may be converted directly to specific gravity in accordance with instructions found 

in the Brix section of this manual, Sucrose Conversion Tables. Products may be carefully 

measured into a suitable and accurately graduated receptacle if it is difficult or inconvenient to 

determine the specific gravity. If requested by the applicant, the net contents may be reported in 

terms of both weight and volume 

Conversion factors for canned foods 

The following table designates common conversion factors that are applicable to most canned 

fruit and vegetable products. If an exact conversion does not exist, choose the closest can size. 

Columns "A" and "B" indicate the number of cans equal to each of the cans designated in the 

"Can Size" column. 

Columns "C", "D" and "E" apply to the case equivalents for the can sizes, and the common 

packing per case.

Fluid ounces =
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Conversion Factors 

A B C D E

 Factors For Converting

Can Size # per case No. 2 cans No. 2 1⁄2 cans Cases 24/2 Cases 24/2 1⁄2 Cases

6/10

5 oz 48 0.235 0.162 0.47 0.324 0.352

6 oz 48 0.295 0.203 0.590 0.406 0.440

8 oz short 48 0.385 0.266 0.770 0.532 0.576

8 oz tall 48 0.422 0.291 0.844 0.582 0.632

No. 1 picnic 48 0.532 0.367 1.064 0.734 0.800

No. 1 1/4 48 0.704 0.485 1.408 0.970 1.060

No. 300 48 0.740 0.500 1.480 1.200 1.112

No. 1 tall 48 0.810 0.559 1.620 1.118 1.224

No. 303 24 0.821 0.566 0.821 0.566 0.616

No. 1 square 24 0.843 0.581 0.843 0.581 0.632

No. 2 24 1.000 0.690 1.000 0.690 0.750

No. 2 1⁄2 24 1.450 1.000 1.450 1.000 1.087

No. 2 1⁄2 square 24 1.585 1.093 1.585 1.093 1.188

No. 3 24 1.710 1.179 1.710 1.179 1.284

No. 3 cylinder 12 2.516 1.735 1.258 0.868 0.943

No. 5 12 2.882 1.987 1.441 0.994 1.080

No. 10 6 5.336 3.680 1.334 0.920 1.000

No. 12 6 6.745 4.652 1.686 1.163 1.264

 
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Examples: 

 1. To find the equivalent number of No. 2 1⁄2 cans:

100,000 cans No. 2 size = (100,000 x 0.690) = 69,000 No. 21⁄2 size cans

 2. To find the number of cases 24/2 1⁄2: 

7,000 cases 24/2 = (7,000 x 0.690) = 4,830 cases 24/21⁄2 

10,000 cases 6/10 = (10,000 x 0.920) = 9,200 cases 24/2 1⁄2 

Sizes of glass containers

Net weights for canned fruits and vegetables in glass are not mandatory. Federal 

and various State laws require that a statement of net contents be given on the 

label, but none of these laws specify what the weights must be. Label weights 

shown on these products generally state the contents for what is considered normal 

fill for the product. Variations in weights are to be expected. The following 

weights represent an approximate average weight of the product and packing 

medium inside the container. 

Capacity of Glass Containers 

Designation

Glass Containers

(overflow) Fluid oz.

Metal

Container oz.

Designation and Size 

of Equivalent Can Size

Baby Jar 5.1 4.9 5 oz 211 X 200

Junior Jar 8.1 7.9 8 oz short 211 X 300

16 oz. Jar 17 16.6 No. 1 tall 301 X 411

No. 303 Jar 17 16.85 No. 303 303 X 406

No. 21⁄2 Jar 28.4 29.75 No. 21⁄2 401 X 411

46 oz. Jar 49 51.62 No. 3 cylinder 404 X 700
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Packing of Glass Containers 

Capacity of Glass Containers

(fluid ounces)

Maximum Number

of Units per Box

Number of Tiers

per Box

8 ounces or less 48 2

over 8 oz. to 17 oz. 24 1

over 17 oz. to 40 oz. 12 1

over 40 oz. to 70 oz. 6 1

over 70 oz. to 1 gallon 4 1 

Calculating drained weight for unpublished container sizes 

A. Drained weights in the United States grade standards are generally published and applied 

by USDA for common container sizes. To determine the recommended minimum drained 

weight for unpublished container sizes on a proportional basis, use the following 

procedure as a guideline: 

1. Refer to tables for Capacity-Sizes of Metal Containers for metal containers, or 

Capacity of Glass Containers for glass containers to find the water capacity of the 

unpublished container. For container sizes not listed in these tables, determine the 

water capacity of the target container by following the procedure in Procedure to 

Determine the Water Capacity in section F. 

2. After obtaining the water capacity of the target container, find the water capacity 

of the next closest container given in the standard. 

3. Divide the recommended minimum drained weight of the closest container by its 

water capacity to get the proportional water capacity.

4. Multiply the water capacity of the target container by the proportional water 

capacity of the nearest container to establish the new recommended minimum 

drained weight for the target container. Round to the nearest tenth of an ounce, 

rounding up for digits ending in 5 or greater, rounding down for digits ending in 

numbers less than 5. Record both the range of results and the drained weight 

average on certificates. Refer to the AIM Inspection Series, Certification Manual

for questions on certification.

Use this equation: 

X = A x B ÷ C; where, 
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X = Recommended minimum drained weight of unknown container,

 A = Recommended minimum drained weight of closest container size, 

B = Water capacity of the target container, and

C = Water capacity of the closest container.

 

Example: Canned Tomatoes in No. 12 cans (603 x 812) 

The water capacity of the No. 12 can is to be 138.35 ounces. (See Capacity-Sizes 

of Metal Containers) The closest can size given in the standard is the No. 10 can, 

which has a water capacity of 109.45 ounces. The drained weight for canned 

tomatoes in the No. 10 can is 63.5 ounces for U.S. Grades A and B. The 

corresponding drained weight of tomatoes in a No. 12 can is calculated as follows:

 X = unknown drained weight, A= 63.5 oz., B= 138.35 oz., C= 109.45 oz., so, 

X = 63.5 oz. x 138.35 oz. ÷ 109.45 oz.; X = 63.5 x 1.26; X = 80.3 oz. for A or B 

grade Canned Tomatoes in No. 12 cans. 

Procedure to Determine the Water Capacity

This procedure applies to several types of primary containers: cans, glass, and plastic (except 

polyethylene or other thin plastic film). Use three containers to determine the water capacity, 

unless the weight of the primary container is a very small percentage of the gross weight and is 

quite uniform. If this is the case, use a single container from the lot to determine water capacity. 

The following is an excerpt from 21 CFR, 130.12, "General Methods for Water Capacity and Fill 

of Containers" which may be found at the following internet address: https://www.ecfr.gov/cgibin/ECFR?page=browse. 

A. To determine the water capacity of a container:

1. If the container has a lid attached by a double seam, cut out the lid without 

removing or altering the height of the double seam. 

2. Wash, dry, and weigh the empty container. 

3. Fill the container with distilled water at 68 degrees Fahrenheit to 3

/16 inch vertical 

distance below the top level of the container. If the container has a lid attached 

other than by double seam, remove the lid and fill the container to the level of the 

top. 

4. Weigh the filled container. 
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6. Subtract the container tare weight from the full container weight. The difference is the 

weight required to fill the container. 

Containers for frozen fruits and vegetables 

Common consumer size containers for frozen fruits and vegetables are 10 ounce, 12 ounce, 14 

ounce, and 16 ounce packages, depending upon the commodity. Some products are also packed 

in larger containers for institutional purchases. Vegetables packed in 2 1⁄2 pound and 5 pound 

packages, and fruits in 2 1⁄2 pound, 10 pound, 15 pound, and 30 pound containers are the most 

common. 

The percentage figures for losses in preparation of raw product for freezing are approximate and 

are only given for estimates.
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Containers for Frozen Vegetables 

Vegetables Common Packages and Usual 

Packing Per Case

Approximate Losses in Preparation of 

Raw Product for Freezing

Asparagus 12-2 1⁄2 lb.

12-8 oz.

24-12 oz.

24-10 oz.

54%

Beans, Lima 12-2 1⁄2 lb.

24-12 oz.

63%

Beans, Green 12-2 1⁄2lb.

24-12 oz.

24-10 oz.

21%

Broccoli 8-4 lb.

12-2 lb.

24-10 oz.

45%

Brussels

Sprouts

8-4 lb.

12-2 lb.

24-10 oz.

45%

Carrots 12-21⁄2 lb. 50%

Cauliflower 8-4 lb.

12-2 lb.

24-10 oz.

70%

Corn 12-2 1⁄2 lb.

24-12 oz.

24-10 oz.

76%

Peas 6-5 lb.

12-2 1⁄2 lb.

24-12 oz.

24-10 oz.

60%

Carrots and Peas 12-2 1⁄2 lb.

24-12 oz.

60%

Spinach 12-3 lb.

12-2 1⁄2 lb.

24-14 oz.

45%

Squash, Pumpkin 24-1 lb. 35%

Succotash 24-12 oz.

24-11 oz.

24-10 oz.

35%

Mixed

Vegetables

12-2 1/2 lb.

24-12 oz.

35%
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Containers for Frozen Fruits 

Fruits Common Packages and Usual 

Packing Per Case

Approximate Losses in Preparation of 

Raw Product for Freezing

Apples 30 lb. 50% 

Apricots 

30 lb.

10 lb. 

24-1 lb. 

22% 

Blackberries

Barrels

30 lb.

5% 

Blueberries Barrels

30 lb.

 

5% 

Cherries

Barrels

30 lb.

25% 

Peaches

30 lb.

10 lb.

33% 

Prunes and

Plums

Barrels

30 lb.

15% 

Raspberries

Barrels

30 lb.

15% 

Rhubarb 

30 lb.

24-16 oz.

15% 

Strawberries

Barrels

30 lb.

7% 

Youngberries,

Loganberries,

Boysenberries

Barrels

30 lb. 

10 lb. 

5% 

Approximate shipping weights 

Shipping weights include the gross weight of the product, primary container, shipping container, 

and any incidental packaging material. Gross shipping weights may be used in determining the 

approximate number of cases that common carriers or transportation lines allow per freight car or 

truck. These weights are also required on bills of lading or manifests. 

The approximate shipping weights shown are for guidance only and are common weights for 

most processed fruits and vegetables. 
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Approximate Gross Weights per Case 

Type of pack

Fruits

(Canned)

Vegetables

(Canned)

Metal Containers, Fiber Cartons

48 - 8 oz.

35 lb. 35 lb.

48 - No. 1 tall

64 lb. ---

48 No. 1 picnic

--- 43 lb.

24 No. 2

39 lb. 39 lb.

 24 No. 2 1⁄2 56 lb. 55 lb.

6 No. 10

49 lb. 48 lb.

Fruits (dried)

Packages and

Fiber Cartons

Wood Boxes

48 - 16 oz.

50 lb. ---

36 - 16 oz.

40 lb. ---

36 - 11 oz.

31 lb. ---

25 lb.

--- 28 lb.

30 lb.

--- 33 lb.

50 lb.

--- 55 lb.
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Length-Inches and Millimeters-Equivalents of Decimal and Binary Fractions of an Inch in Millimeters 

1/2's 1/4's 8th's 16th's 32nd's 64th's Millimeters

Decimals 

of an inch Inch 1/2's 1/4's 8th's 16th's 32nd's 64th's Millimeters

Decimals 

of an inch

1 0.397 0.015625 33 13.097 0.515625

1 2 0.794 0.03125 17 34 13.494 0.53125

3 1.191 046875 35 13.891 0.546875

1 2 4 1.588 0.0625 9 18 36 14.288 .5625

5 1.984 0.078125 37 14.684 0.578125

3 6 2.381 0.09375 19 38 15.081 0.59375

7 2.778 0.109375 39 15.478 0.609375

1 2 4 8 3.175 0.125 5 10 20 40 15.875 0.675

9 3.572 0.140625 41 16.272 0.640625

5 10 3.969 0.15625 21 42 16.669 0.65625

11 4.366 0.171875 43 17.066 0.67875

3 6 12 4.762 0.1875 11 22 44 17.462 0.6875

13 5.159 0.203125 45 17.859 0.703125

7 14 5.556 0.21875 23 46 18.256 0.71875

15 5.93 0.234375 47 18.653 0.734375

1 2 4 8 16 6.350 0.25 3 6 12 24 48 19.050 0.75
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1/2's 1/4's 8th's 16th's 32nd's 64th's Millimeters

Decimals 

of an inch Inch 1/2's 1/4's 8th's 16th's 32nd's 64th's Millimeters

Decimals 

of an inch

17 6.747 0.265625 49 19.447 0.76525

9 18 7.144 0.28125 25 50 19.844 0.78125

19 7.541 0.296875 51 20.241 0.796875

5 10 20 7.938 0.3125 13 26 52 20.638 0.8125

21 8.334 0.328125 53 21.034 0.828125

11 22 8.731 0.34375 27 54 21.431 0.84375

23 9.128 0.359375 55 21.828 0.859375

3 6 12 24 9.525 0.375 7 14 28 56 22.225 0.875

25 9.922 0.390625 57 22.622 0.890625

13 26 10.319 0.40625 29 58 23.019 0.90625

27 10.716 0.421875 59 23.416 0.921875

7 14 28 11.112 0.4375 15 30 60 23.812 0.9375

29 11.509 0.453125 61 24.209 0.953125

15 30 11.906 0.46875 31 62 24.606 0.96875

31 12.30 0.48475 63 25.003 0.984375

1 2 4 8 16 32 12.700 0.5 1 2 4 8 16 32 64 25.400 1.000
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ENZYME INACTIVATION

Inactivation of the peroxidase and catalase enzymes is achieved by the proper blanching of 

vegetables prior to freezing. These enzymes would otherwise cause development of off-flavors, 

loss of color and loss of vitamin A and C during storage after freezing. Blanching also tends to 

fix the characteristic color of vegetables. Better color retention is attained by blanching at a 

higher temperature for a short time, rather than through lower temperatures for a longer time. 

Over-blanching may cause dull color, flavor loss, sloughing, and poor texture. 

For the majority of vegetables, inactivation of catalase alone does not indicate adequate blanch. 

Inactivation of the peroxidase enzyme is considered necessary to minimize future deterioration in 

quality. Consequently the Peroxidase test is considered the official Division test for enzyme 

inactivation. For properly blanched products, test results are negative. 

Lot Inspection Procedures 

Products inspected under lot inspection will not routinely be tested for enzyme inactivation. The 

peroxidase test will be made on all condition inspections, or if required by Federal or buyer's 

specifications, or if requested by the applicant. In addition, the peroxidase test will be run during 

inspections of frozen vegetables if there is organoleptic evidence of under-blanch such as offcolors, off-flavors and toughening. 

When specifications call for catalase or tests other than the peroxidase test, or specify methods 

other than the USDA methods contained in this technical manual, such tests should be performed 

as required by the specification.

When required, the minimum rate that enzyme inactivation tests be performed: 

Quality

Sample Size

Number

of Tests

3 1

6 1

13 3

21 3

29 4

Additional tests should be made if organoleptic inspection indicates the possibility of inadequate 

blanching. 

In-Plant Inspection Procedures 

All vegetables processed and frozen under in-plant inspection (except onion rings, sweet peppers, 

rhubarb, French fried potatoes, and cooked squash) are to be tested for peroxidase inactivation. 

Where required by Federal, buyers, or other specifications, testing for catalase inactivation must 

be in addition to the peroxidase test. Testing using methods outlined in specifications is 
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permissible in lieu of the USDA method when inspection and certification are based on such 

specifications. Samples from each blancher are to be tested at the beginning of every processing 

period. Additional sample units should be tested whenever there is an indication that the blanch 

may have changed. Tests should also be made at least hourly throughout the shift. 

Quality Control Testing – Unofficial

The official peroxidase test and other enzyme inactivation tests are useful quality control tools. 

For example, blanch temperature may be adjusted so that a peroxidase test will show no color 

development within three and a half minutes but will show color development within eight 

minutes. It is most useful to test the larger units of product for peroxidase activity. Depending 

upon the variation in product unit size, if there is color development in two and a half or three 

minutes, the product may be considered neither under nor over blanched, and official tests with 

units representative of all unit sizes may remain negative. 

Indications of possible under blanching include low initial blanch temperature, drops in 

temperature, increased volume of product, or increase in unit size of product, which suggests the 

need for additional quality control checks. Quality control tests from isolated portions of 

production can and should be made for those plants relying on the inspector for help in quality 

control. This should be noted on the score sheet, but not be considered the official routine 

peroxidase test unless representative of the production. Similarly, quality control tests on larger 

units may be recorded on the score sheets, but this should be noted as being a restrictive test and 

not one of the routine representative tests for the hour. 

Quality control tests may be made on the cut surface of an individual unit of product, but these are 

not considered official tests. Pieces of the product can be tested with 0-tolidine paper and 

hydrogen peroxide (H202) to show the extent of any unblanched area in a piece of product, and to 

show variations among pieces of the same size in judging the uniformity of the blanch. 

Special Tests for Certain Products

A. Broccoli:

For quality control purposes, test the top center portion of the heads of the large stocks 

where enzyme activity will be concentrated, if present. This may give quality control 

additional information but is not to be considered an official test. 

B. Brussels Sprouts 

Quality control checks can include the development of pink centers soon after freezing 

and storage, or the rapid development of pink color after about 15 seconds with the 

addition of 1⁄2 to 3 percent H202 to the cut surface immediately after blanching. Correlation 

of one of these tests with the official test should provide a rapid quality control check. 
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C. Corn-on-the-Cob 

When testing corn-on-the-cob, use only the kernels removed from the cob. Scrapings 

taken from the cob at the base of the kernels may show residual peroxidase activity even 

though the product is adequately blanched. 

Size, Collection and Handling of Sample Units

Use a 200-gram sample that is representative of the variation in piece sizes. If some pieces are 

very large, all pieces shall be cut in quarters, and a quarter from each piece used for the 200 gram 

sample.

Blanched, cooled, unfrozen samples should be taken just before entering the freezer. Test within 

1⁄2 hour, or quickly cool to 35 degrees F in ice water or in a freezer compartment and run the test 

within 2-3 hours. 

Frozen samples should be water thawed in tap water at no more than 86 degrees F until units can 

be easily separated. Do not perform test on completely frozen sample units. Enzyme tests must

be completed within 30 minutes of thawing. 

Peroxidase Testing Procedure 

A. Reagents

1. Distilled Water.

2. 0.5 percent guaiacol in either 50 percent ethyl alcohol solution or a 50 percent 2-

propanol (isopropyl alcohol) solution. 

3. 0.08 percent hydrogen peroxide (2.8 ml of 30 percent hydrogen peroxide made up 

to a liter with distilled water). Keep in refrigerator in a dark bottle and replace 

each week or two.

B. Apparatus 

1. Test tubes - 3⁄4 or 7/8 inch diameter 

2. Funnels - 3 or 4 inch diameter 

3. Cotton milk filters - 6 or 7 inch diameter or SS 604 filter paper or similar quality, 

18.5 cm. in diameter. 

4. Mechanical blender 

5. Graduated cylinder - 50 ml
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6. Pipettes - 1 ml and 2 ml 

7. Timer or watch with second hand 

8. Test tube rack

9. Balance with an accuracy of ± 0.1 gram

C. Procedure 

1. The test must be completed within 30 minutes after the product is thawed. 

2. Weigh out a representative 200 gram sample. (See 89.) 

3. Place in blender with 600 ml of water. 

4. Macerate for 1 minute at high speed. 

5. Filter through cotton milk filter. If cotton milk filters are not available, SS 604 

filter paper may be used. Discard the first 5-10 ml of filtrate.

6. Prepare a blank by adding 21 ml of distilled water to 2 ml of filtrate in a test tube. 

Add 1 ml of 1⁄2 percent guaiacol solution without mixing. Do not add any 

hydrogen peroxide to this tube. 

7. Prepare the sample by adding 20 ml of distilled water to 2 ml of filtrate in a second 

test tube. Add 1 ml of 1⁄2 percent guaiacol solution without mixing. 

8. Add 1 ml of 0.08 percent hydrogen peroxide to the second test tube without 

mixing. See illustration.

9. While wearing gloves, mix contents of both tubes thoroughly by inverting each 3 

times and returning to test tube rack. Watch for development of any color in the 

sample tube to which hydrogen peroxide was added. Use the blank tube 

containing guaiacol, water and filtrate for comparison. Any color change in the 

sample tube that is in obvious contrast to the blank is considered a positive test. If 

no such color contrast develops in 3 1⁄2 minutes*, consider the test negative and the 

product adequately blanched. If color develops after 3 1⁄2 minutes, it is to be 

disregarded, and the test still considered negative. 

Zucchini Squash: 1 minute. 

Brussels Sprouts: 2 1⁄2 minutes; however, consider test results on the lot as 

meeting if no more than 1 of 3 sample units tested changes after 2 minutes. 

A lot fails if any sample units change color before 2 minutes. 
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PEROXIDASE TEST

 Number 1 Number 2

 (Blank) (Test Sample)

Note: Use only 3/4 or 7/8 inch diameter test tubes. 

Catalase Testing Procedure

A. Reagents

 1. Distilled water

 2. Calcium carbonate (CaCO3) 

3. 3 percent hydrogen peroxide (10 ml of 30 % hydrogen peroxide per 100 ml of 

distilled water). Keep in refrigerator in a dark bottle.

B. Apparatus 

1. Mechanical blender

2. Footed fermentation tube with vertical tube graduated from 0 to 5 ml in 1/10 ml 

graduations (Kimble 46162, or similar). 
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3. Funnels - 3 or 4 inch diameter 

4. Cotton Milk filters - 6 or 7 inch diameter, or SS 604 filter paper or similar quality, 

18.5 cm. in diameter.

5. Pipettes - 1 ml, 5 ml, and 10 ml 

6. Balance with accuracy of ± 0.1 gram.

7. Timer or watch with second hand. 

C. Procedure 

1. Comminute a 100-gram portion of vegetable material together with 100 ml of 

water and about 2 grams of calcium carbonate.

2. Filter slurry through cotton milk filter.

3. Add 2 ml of distilled water to the fermentation tube (See illustration on the 

following page). 

4. Pipet 2 ml of filtrate into tube.

5. Add 8 ml of 3 percent hydrogen peroxide to tube. 

6. Invert tube in such a manner as to completely fill the calibrated column. Tap 

gently to dissipate any bubbles that result from mixing the solution.

7. Return to upright position and allow contents to generate for 3 1⁄2 minutes. 

8. At the end of 3 1⁄2 minutes, record the volume of gas formed. 

9. A reading of 0.1 ml or less is considered negative for the catalase enzyme; any 

reading of more than 0.1 ml is considered positive. 
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Certification

Official peroxidase or catalase tests that are representative of a production period or lot are shown 

on the score sheets for the item, but are not reported on a certificate unless: 

1. Requested by the Applicant. 

2. Required by Federal, Buyer's or other Specification.

3. Inspection is for condition of the product, and some of the samples are positive. 

Refer to the AIM Inspection Series Certification Manual for appropriate statements to be shown 

in the "Body" and/or "Grade" section of a certificate. 

FROZEN AND REFRIGERATED PRODUCT

SCI Division offices periodically get requests for inspecting and reporting the temperature and 

condition of refrigerated and frozen foods. Normally requests for this type of restricted inspection 

are from packers, buyers, or carriers; they may be either the result of dispute or rejection of 

deliveries because of alleged high temperatures upon arrival at terminal warehouses; or the 

interested party is using the data as a part of a quality control program. Many times condition 

inspection will involve small lots of commodities not assigned to the Fruit and Vegetable 

Program. Do not examine or report conditions of commodities other than those assigned to our 

Division. Temperatures on such commodities may be taken and reported when they are part of a 

mixed load. Contact your immediate supervisor if you question the assignment of a commodity. 

Catalase

Fermentation

Tube 

Air bubbles collect 

here. Read from 

the bottom of the 

collection.
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Inspection Request

It is very important to obtain sufficient information when taking applications for condition 

inspections on refrigerated and frozen products. 

• If frozen, has the lot been thawed? If so, is it now refrozen? 

• Does the applicant want the certificate restricted to condition and/or product temperature? 

• Does the applicant want certification of quality, condition, and/or product temperature? 

When taking the application, be sure the applicant understands the various options available. 

• Inspection and certification may be restricted to temperature only. Inspection and certification 

may be restricted to condition only, condition meaning condition of containers and packaging, 

condition of product (no grade determination), and temperature of product. 

• Inspection and certification may include a quality determination in addition to all of the 

condition criteria previously stated, except that no quality evaluations will be made on frozen 

product unless the product is frozen. See the AIM Inspection Series Certification Manual for 

conditions under which certification may be applicable.

Sampling

For Condition of Containers, follow sampling procedures outlined in the AIM Inspection Series 

Condition of Food Container Manual. For product quality, condition, and temperature, as a 

minimum use the single sampling plan in the regulations. Increase sample size as needed.

Fill out the certificate of sampling as directed in the AIM Inspection Series, Sampling Manual

with the following special notes: 

• Record the time the product is sampled and temperature noted; 

• Record pertinent information obtained from the rail car or truck temperature recording 

devices, thermometers, and any other useful information from the shipping documents; 

• If the product is in a cold storage room and has recently been transferred from a “hot” carrier, 

attempt to locate documentation that may corroborate when the transfer took place; and 

• Record the condition of the primary and secondary containers, especially noting stains, 

wetting, collapsed cases, etc.

Equipment used for Checking Temperatures

The quality of frozen foods changes with time and the temperature of storage. Packers, shippers, 

carriers, distributors, retailers and regulatory agencies are interested in the maintenance of proper 
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temperatures for the protection of frozen products. One measure of control is to check the 

product at various points in the distribution channel to assure maintenance of proper temperatures. 

A. Temperature quality control starts with the use of an accurate, reliable thermometer. 

There are various thermometers and instruments available to take temperatures of frozen 

foods. The most common types are: 

1. Metal dial thermometer, with the following characteristics:

a. A pointed stainless steel stem, approximately 5 inches in length.

b. A temperature range of at least -20 degrees F. to +120 degrees F. The high 

end of the range is suggested, so that, if desired, a record may be made of 

the ambient (outside) temperature at the time the commodity temperature is 

taken. Markings on the scale should be in 1 degree or 2-degree divisions. 

c. A hermetically sealed dial.

d. A pocket carrying case to protect the thermometer.

2. Electronic instrument, capable of registering temperatures very quickly. Most of 

these instruments have instantaneous adjustments that recalibrate in a matter of 

seconds. 

B. Thermometers used for checking the temperatures of food products should be tested every 

week, or as often as is necessary to ensure their accuracy. See the “Calibration of 

Equipment” section of this manual for instructions on calibrating thermometers. 

Thermometer s must be handled carefully and should not be bent, dropped, handled 

roughly, or exposed to temperatures beyond those shown on it. Do not use a thermometer 

as a tool or probe. See the AIM Inspection Series, Sanitation and Safety Manual for 

sanitizing procedures for probes and thermometers. 

Selecting Representative Samples

A. Warehouse Lots.

Draw the number of samples specified in the single sampling plans as shown in the 

Regulations. Select the samples in accordance with the sampling procedures in the AIM 

Inspection Series Sampling Manual. 

B. Railroad Car or Truck Lots

At time of loading, test the product in several packages in the warehouse before the 

packages are loaded into the car or truck. Selecting the test packages is a matter of 

judgment; select them in such a way that their temperatures will be representative of the 

entire load.
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When product is being unloaded, test the product in packages taken from the locations 

shown in the illustration on the next page. These packages should give product 

temperatures representative of the load. Additional packages may be tested if warranted, 

depending upon the type of product, appreciable cold or hot weather enroute, or other 

circumstances. 

Suggested locations to select test packages in the car or truck: 

1. Top, front, center 

2. Bottom, front, center 

3. Top, middle center 

4. Half way up, middle, center 

5. Bottom, middle, center 

6. Bottom, middle, side (next to door if there is a side door) 

7. Top, rear, center 

8. Bottom, rear, center

Method I - Measuring Temperatures by Opening Samples

This method is recommended for precise product temperature measurement. It is sometimes 

referred to as "destructive" testing since some of the product is sacrificed during the process. 

However, in critical cases, the loss of product is small compared to the potential loss of the entire 

lot. Method I is always recommended for products in cans because it is difficult to obtain a firm 

contact between the thermometer probe and sidewall surfaces of the containers. 

A. Use a probe to make a hole in the sample

Make a hole in frozen products with an ice pick, hand drill, or other pointed tool into 

which to insert the thermometer. The tool should be slightly larger (approximately 1/64 

inch larger) in diameter than the diameter of the thermometer stem. This tool will be 

referred to hereafter as a probe.
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B. Equalizing the thermometer

At least 5 minutes before using, place the thermometer and probe inside the car, truck, or 

warehouse where the product is stored in order to equalize their temperatures with the air 

surrounding the product. Because it may give a misleading temperature reading, avoid 

inserting a warm thermometer into a test package. Select a package at random from the 

load to precool the thermometer (referred to as the precool package). The product in this 

package is used to chill the thermometer stem before each insertion into a test package. 

C. Taking the product temperature 

Gently insert the point of the thermometer into the center of the precool package. If the 

thermometer cannot be inserted into the product by gentle pressure, use the probe to make 

a hole to the center of the product. 

Leave the thermometer in the center of the product for at least 30 seconds. Do not remove 

it until you are ready to insert it into the test package.

Then remove the thermometer from the precool package and immediately insert it a 

minimum of 2 1⁄2 inches to the center of the product in the test package (see illustration 

below). Wait at least 2 minutes and read the temperature. If several packages are being 

tested, the thermometer can be left in each test package until the next package is ready for 

testing. 

Method II – Measuring Temperatures without Opening Samples

This method is sufficiently accurate for routine temperature checks. Whenever exact product 

temperatures are necessary, or in the case of any doubt or controversy, Method I should be used in 

lieu of Method II. 

A. Equalizing the thermometer

Follow the same procedure as specified for Method I, Step No. 2. 
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B. Selecting cases

Select 7 cases of frozen foods from the lot in question. Stack any 3 of the 7 on the floor 

area of the cold environment in which the lot is held. 

C. Taking the temperature

Cut sidewall of the top case at one end with a sharp knife. Bend the cut tab outward. 

Insert probe of the temperature measurement device at about the center of the first stack of 

packages, and between the first and second layers of packages so that the entire sensing 

element is in firm contact with package walls (see illustration below). For poly bags, 

insert probe in the same direction as the length of the bag, deep enough for firm contact 

between bags. Stack the other 4 cases on top of the case containing the thermometer.

Read and record the temperature observed when the needle gives a steady reading. This is 

generally 5 minutes or less for a dial thermometer. Close and tape the cut sidewall area of 

the case.

Thawing Procedures

Frozen fruits and vegetables must be thawed to properly evaluate the characteristics of the 

product. Take care that during the thawing process the product is not damaged or exposed to 

abuse that will alter its true characteristics. 

Frozen fruits are more susceptible to abuse during thawing than frozen vegetables. Red cherries 

and light colored fruits such as peaches and apricots will oxidize quite readily and should be 

examined for color while some ice crystals still remain in the product. Some fruits show 

breakdown in texture or "bleed" when thawed. When preparing the product for examination, 

rapid thawing under controlled conditions is ideal. 

There are three general methods for thawing frozen fruits and vegetables: 

A. Air Thawing

B. Water Thawing; and

C. Microwave Thawing.
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Water and Microwave Thawing are faster but may not be suitable for all products. Products thaw 

at different rates. Frozen peas or broccoli thaw much faster than frozen leafy greens. 

Consequently, no specific time can be designated to accomplish adequate thawing. Through 

experience, the inspector will learn to judge the best procedure and time requirement for each 

commodity. 

When air thawing is used, it may be desirable to speed the process by placing the cartons on a 

table so they are well separated by air space, and directing a stream of air from a fan on the 

packages. 

A. Air thawing

1. Frozen Fruits 

Fruits in closed containers may be air thawed until the product is sufficiently free 

from ice that individual units may be readily separated and handled. Rapid 

thawing is most desirable; a fan should be used to speed the process. Do not air 

thaw in open containers. Do not over-thaw.

2. Frozen Vegetables

Air thawing is an alternate procedure to water thawing for frozen vegetables. The 

air thawing method is suggested if there is suspicion of off flavors or odors. It 

should also be considered for products susceptible to insect infestation or sand and 

silt. Do not over-thaw.

B. Water thawing

1. Frozen Fruits 

Fruits may be thawed in a water bath if they are in tightly sealed containers. 

Temperature of the water should not exceed 86oF. Thaw only until the product is 

sufficiently free from ice that individual units may be readily separated and 

handled. A water bath should be used to thaw large bulk containers.

2. Frozen Vegetables

Most frozen vegetables can be thawed directly in water without degrading the 

product. Remove the product from the package and place it directly in the water at 

a temperature not to exceed 86o

F. As soon as the product is sufficiently thawed to 

permit easy separation of the units, drain on a suitable 8 mesh screen to remove 

excess water, and place the product on a tray for examination. Do NOT soak the 

product past the point of sufficient thawing. This is particularly important for 

products such as cut corn. 

Some preliminary checking of frozen vegetables may be necessary if there is any 
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indication or suspicion of an off flavor or odor. If a sample is questionable, do not 

use direct water thawing since any suspect flavor might be diluted by the water. 

Such product may be water thawed in tightly sealed containers or air thawed. 

Place any suspect sample in a covered cooking pan and cook for analysis of flavor 

and odor. 

Some vegetables are susceptible to insect infestation, such as aphids and thrips, or 

sand and silt. In such cases, thaw the product in a suitable container, saving the 

water. Filter the water through a milk filter disk or white toweling and examine 

the filter for any extraneous matter present. Combine any material found in the 

thawing water with any additional material found by other means. 

Note: Some vegetables have Defect Action Levels based on standard sample unit sizes 

and procedures. If so, use the standard procedure. 

C. Microwave thawing

Microwave thawing is not recommended as a standard procedure for either fruits or 

vegetables because all or part of the sample unit may be changed in color or character by 

"hot spots.” However, certain products, such as shredded hash browns and preformed 

potatoes can be quickly thawed to facilitate examination for defects and foreign material. 

After other factors have been evaluated, cherries may be completely thawed and warmed 

in this manner to facilitate pit determination.

If microwave thawing is used as a standard thawing procedure, it should only be done 

after careful experimentation with time and power settings to assure that no undesirable 

changes will take place.

D. Thawing Frozen Strawberries 

These instructions are for thawing and sampling an entire institutional size container 

(weighing more than 10 pounds) of frozen strawberries. The product may be whole or 

sliced frozen strawberries, with or without packing medium. These instructions are not for 

individually quick frozen (IQF) strawberries.

1. In accordance with regulations, select containers to be used for samples. Allow all 

containers to thaw unopened following the procedures outlined in section G, 

“Thawing procedures”.

2. Leave the containers unopened until the strawberries are thawed. When the 

strawberries are sufficiently free from ice crystals and readily separable, stir the 

contents of the containers using a large spoon or ladle, being careful not to damage 

the strawberries. 

3. After the contents of the containers are thoroughly mixed, draw a sample unit 
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weighing approximately three pounds from each container.

4. Follow the instructions in the current Grading Manual for Frozen Strawberries for 

the amount of strawberries to be used for quality and analytical testing.

Note: Determining the grade as soon as possible after thawing minimizes the risk of 

oxidation.

Verification of Frozen Sample Units

Under certain conditions, SCI Division inspectors may be called upon to inspect, grade and 

certify frozen fruits or vegetables using unfrozen sample units drawn from the production line. 

This is applicable to products packed in silos, drums, or bulk institutional size containers (over 10 

pounds), and situations where frozen samples are examined at a later date, or where no frozen 

samples are examined. 

Note: Frozen verification sample units must be examined for all retail and small 

institutional size packages (less than 10 pounds). 

See the AIM Inspection Series, General Procedures Manual and Certification Manual for 

procedures to follow. 

As a prerequisite to assigning the grade to frozen fruits and vegetables, the U.S. Standards state: 

“frozen in accordance with good commercial practice and maintained at temperatures necessary 

for the preservation of the product." Specific temperature limits are not prescribed, although it is 

generally recognized that proper storage temperatures for frozen foods should be zero degrees F 

or lower. A tolerance of 5 or 10 degrees must be made for conditions encountered during 

distribution in which the product may be temporarily held or handled in a manner that allows the 

product temperature to rise above zero degrees F. Private buyers and government agencies may 

have either more stringent or less stringent requirements.

While having no authority to prescribe freezing and storage temperatures, the Division supports 

the concept of "zero degrees F or lower". We recognize that we are often called upon to certify 

products in which the freezing process is not entirely completed and the product has not been 

reduced to a temperature of zero degrees F. In the absence of specific instructions otherwise, we 

will not certify the grade of a frozen product if the temperature is in excess of 15 degrees F. This 

does not mean that we condone temperatures above zero degrees F. It is merely an administrative 

allowance to facilitate inspection and certification prior to the completion of the freezing cycle.

A final U.S. grade shall not be assigned to a production lot until frozen product sample units have 

been officially drawn and evaluated, regardless of how many line check sample units have been 

taken. The total number of sample units examined must equal or exceed the minimum number 

required for the single sampling plan or time sampling plan for each lot size of one grade, style, 

container size, etc. To meet this requirement, it may be necessary to grade additional frozen 

sample units from the cold storage. 
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If an insufficient number of line check samples were drawn during production, a number of frozen 

sample units must be completely graded to meet the minimum number of samples required. 

However, if sufficient line check sample units were drawn to meet the minimum number of 

samples for the lot size, then the frozen sample units need only to be evaluated for those factors 

which may change during freezing, such as, color, character, and flavor. Frozen verification 

samples should be properly thawed following the procedures in Section G, "Thawing 

Procedures." The units should be separated to determine whether product deterioration was due 

to oxidation, crystallization, or other causes. 

A. Sampling

The verification sample units should be drawn as duplicates of the line check sample units. 

The duplicate sample units should be marked for identification with the line check and to 

assist in retrieval from the cold storage. The verification subsamples should be handled, 

transported, and stored in the same manner as the bulk containers in the lot that it 

represents. 

Note: The above procedure is not applicable to drums and other large containers where 

verification subsamples are taken from the processing line. 

When verification results indicate product condition is abnormal or product quality has 

been impaired, the line check results cannot be considered reliable. Samples must be 

drawn from the cold storage for complete grading at the sampling rate indicated in the 

Regulations, and the AIM Inspection Series Sampling Manual. 

If specific instructions indicate that the examination of more frozen sample units is 

necessary, follow those instructions. 

B. Sample size

When the cold storage is located where the product is produced, and the freezing results in 

product that retains its initial quality characteristics, then the minimum sample size for 

verification of frozen product is one frozen sample unit per shift from each lot of a single 

grade, style, and container size, regardless of the size of the lot.

When the cold storage is located at a different location from the processing plant, and 

conditions under which the product is transported and stored are not known, then the 

sample size for verification of frozen product shall be in accordance with the table below. 

Sample Size for Verification of Frozen Products

 Sample Size Drawn for Quality 3 6 13 21 29 

Sample Units Drawn for Verification 1 2 3 4 5 
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C. Recording verification results 

When there is a U.S. grade standard, product verification results will be recorded as score 

point values, or quantity and type of defects found, or by letter grades. If there is no U.S. 

grade standard, use the appropriate descriptive terms to describe a quality level (see AIM 

Inspection Series General Procedures Manual).

E. Re-inspection of affected lots 

When temperatures of affected lots are reduced to acceptable levels in storage, they may 

be sampled, re-inspected and certified as to grade. The normal sampling rate for such reinspections will be determined from the appropriate table in the Regulations.

After three consecutive lots have been re-inspected using the normal sampling rate, a 

reduced rate may be considered. This rate will be based on the inspector's knowledge of 

the product, and the ability of the processor to reduce high temperature production to 

certifiable levels quickly without detrimental effects on product quality. In any event, the 

inspector must sample and completely inspect a sufficient number of sample units to 

assure the correct certification of the lots as "frozen".

F. Approved identification 

It is necessary to protect the integrity of production that has been packaged under 

"Approved Identification," marks. In this case, a lot with temperatures 16 degrees F or 

higher must be placed on "hold" until a final grade can be determined. Should this lot be 

found to be substandard or a lower grade than indicated, the marks must be removed 

before the product leaves the plant. (See the AIM Inspection Series General Procedures 

Manual, and the Regulations.) 

G. Cautions and exceptions 

These instructions do not apply when inspection and certification are based on a 

specification or exceptions which conflict with the temperature limits set forth. 

Examples of such conflicts are:

1. The temperature limit of + 5 degrees F that is required for frozen concentrated 

citrus products, 

2. The temperature requirement of zero degrees F that is established in the standards 

of identity for frozen peas, 

3. The requirements that are established by either USDA or DSCP for purchases of 

frozen foods, or 
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4. The following on-line temperature exception for frozen french fried potatoes. This 

exception does not apply to frozen hash brown potatoes. When temperatures of 

frozen french fried potatoes checked off the line are between 16 and 19 degrees F, 

the product may be given a final grade and certified only if:

a. It has been placed in zero degrees F (or less) storage temperatures for a 

minimum of 24 hours. 

b. The inspector verifies storage temperatures on a daily basis. 

Cooking Procedures 

Final examination of many frozen products requires preparation by cooking, particularly frozen 

vegetables. In some cases, cooking is required for product examination of texture, tenderness or 

maturity. In other cases there may be a question regarding the flavor of the prepared product. 

Most frozen vegetables are blanched or partially precooked during preparation for freezing. The 

freezing process softens the tissues, and frozen vegetables require only from one-third to one-half 

as much cooking time as does the fresh product. Take care to neither overcook nor undercook the 

product. 

When checking flavor, take care to prevent dilution of any off or objectionable flavors by 

exposure to excessive water. Suspect containers can ordinarily be identified by odor as the 

package is opened and prepared for inspection. If an off-odor is noted, the container(s) should be 

evaluated for flavor.

A. Sample selection

Generally, we do not take a separate set of samples strictly for cooking purposes. The 

exception might be in the case of bulk or institutional type containers, when enough 

product is available that a portion of each container can be allocated for visual 

examination, chemical or physical tests, and (in the frozen state) for cooking. Usually the 

inspector will only have the same samples used to evaluate other product characteristics

available for cooking. With this in mind, complete testing can be performed by careful 

segregation and planning during the process of product examination. 

In the case of retail size packages (16 ounces or less), all of the container packages may be 

partially or completely air thawed and checked for suspect off-odors and flavors. Portions 

of suspect samples should be cooked for further odor and flavor evaluation. If the odor of 

the thawed product is normal, proceed with product examination and cook representative 

portions of the samples for whatever checks may be required. If the packages are very 

small, it may be desirable to draw additional containers for cooking purposes only. 

Note: Inspectors shall note on the applicable tally sheet or score sheet which sample units 

were cooked.
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B. Seasonings 

For the purpose of laboratory testing, it is recommended that seasonings such as salt, 

sugar, butter, vinegar, or spices be avoided; such additives may cover up undesirable or 

off-flavors that may be present. 

C. Cooking method 

Most vegetables are cooked without thawing. However, for inspection purposes, it may 

be necessary to cook a product that is partially or completely thawed since portions of the 

sample may have been used for other examinations or tests. Be guided by the standard for 

the product. 

The following steps will assure uniformity in the cooking of frozen vegetables for test 

purposes: 

1. Using a two-quart saucepan, bring about 180 ml of water to a boil and add 

approximately 8 ounces (225 grams) of product to the pan. 

2. Bring contents to a rapid boil and continue to heat sufficiently to maintain a rolling 

boil. 

3. Start timing the cook from the moment the water returns to a boil after the 

vegetable is added.

4. During the cooking process, keep a reasonably tight-fitting cover on the pan to 

avoid excessive loss of water.

5. Continue the cooking for the period of time specified for the product (see the 

recommended cook times). 

Note: Cooking time may vary within range specified depending upon variety, maturity, size of 

pieces, and degree of blanching. See label cook time.

6. At the end of the cooking period, drain any excess water and place the cooked 

product on a tray. 

7. Allow to cool sufficiently to be comfortably warm and make the required 

organoleptic tests. 

D. Recommended cook times: 

The following table is the recommended cook time for various products: 
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Product Time (Minutes)

Asparagus, small and medium sizes 5 to 7

Asparagus, large and very large sizes 7 to 9

Green Beans 8 to 10

French Cut Green Beans 4 to 6

Italian Green Beans 4 to 6

Lima Beans (thin seeded) 15 to 18

Lima Beans (thick seeded) 12 to 15

Broccoli 5 to 7

Brussels Sprouts 8 to 10

Carrots 6 to 8

Cauliflower 3 to 5

Corn (whole kernel) 2 to 4

Corn-On-The-Cob 3 to 5

Leafy Greens:

Collards, Kale, Mustard, Turnip 20 to 25

Spinach (leaf) 3 to 4

Spinach (chopped) 2 to 4

Mixed Vegetables 9 to 12

Okra 8 to 10

Peas 3 to 5

Black eye or Field Peas 40 to 45

Peas and Carrots 6 to 8

Squash (summer) 5 to 7

Succotash 8 to 10

Fruit – Sugar Ratio 

Determination and certification of proportion of fruit to packing medium is an important element 

in the inspection and certification of frozen fruits. This is valuable data for both the seller and 

buyer, especially if the product is intended for further processing into jam or preserves. For these 

products, it is essential that the user know the fruit content (or proportion of fruit to packing 

media) in order to adjust the formula to meet mandatory Food and Drug Standards of Identity. 

These require a minimum of 45 parts of fruit ingredient (exclusive of added sweeteners) to each 

55 parts of sugar solids. 

The fruit and sugar content of frozen fruits and berries is not a requirement of the United States 

Standards, and an official form for calculating Fruit-Sugar ratios, or noting observations that 

confirm the ratio being packed has not developed. However the product needs to be packed in 

accordance with good commercial practice, and must also conform to provisions of the Federal 

Food, Drug, and Cosmetic Act with respect to labeling. Even for products not covered by 
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mandatory standards, it is important for the user to have reasonable assurance of the fruit content 

of the frozen fruit ingredient as well as the quality of the finished product. 

Many buyers specify a proportion of fruit to sugar as a part of their requirements. Berries and 

fruits are packed with varying amount of added sugar, ranging from a "straight pack" with no 

added sugar, to what is known as 7 + l, 6 + l, 5 + l, 4 + l , 3 + l, etc. Unless otherwise specified, 

these ratios are understood to mean a dry sweetener rather than a liquid packing medium, and 

sucrose rather than other sweeteners. The first number indicates the proportion of fruit and the 

second number the proportion of sugar. For example, a 3 + 1 pack means 3 parts by weight of 

fruit and 1 part by weight of dry sugar. 

Some fruits are packed with a liquid sweetened packing medium and may be labeled to indicate 

the proportion of fruit to liquid media as "5 parts fruit to l part 60 degrees Brix syrup." These 

ratios such as 5 + 1 could be expressed as “5 to 1”, “5 x 1”, or “5 : 1,” all meaning the same thing. 

Assuming the merchandise is accurately labeled or represented, the buyer or receiver can readily 

ascertain the weight of fruit ingredient and the weight of sugar in a given container or lot. 

For example, the proportion of ingredients in a 400-pound barrel of frozen berries packed with 

different declared proportions of fruit and sugar is calculated as follows: 

Example: If declared as 5 + 1 (5 parts fruit, 1 part sugar), then 5/6 of the contents is 

fruit and 1/6 is sugar. 

Fruit = (5/6 ) (400) or 333 1/3 pounds 

Sugar = (1/6 ) (400) or 66 2/3 pounds 

Example: If declared as 3 + 1 (3 parts fruit l part sugar),

 then 3/4 of the contents is fruit and 1/4 is sugar. 

 

Fruit = (3/4) (400) or 300 pounds 

Sugar = (1/4) (400) or 100 pounds 

Example: If declared as 4 parts fruit and 1 part 60 degrees Brix syrup, then 4/5 of the 

 contents is fruit and 1/5 is packing medium.

Fruit = (4/5) (400) or 320 pounds 

Syrup = (1/5) (400) or 80 pounds 

Calculate the amount of added sugar in the packing media as follows: 

60 degrees Brix syrup means 60 percent sugar solids. 

(80) (0.60) = 48 pounds of sugar solids, and the remaining 32 pounds is 

water from the liquid packing medium. 
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However, the precision of these figures depends on the accuracy of the packer in maintaining the 

correct fruit and sugar proportions during processing. Direct observation of the processing 

operation is the most reliable method for determining fruit-sugar ratio. 

Verification of Fruit – Sugar Ratio: In-Plant Inspection

Processors may need to ascertain the fruit-sugar ratio of products in order to formulate for various 

receivers, or to meet mandatory FDA requirements. The proportion of fruit to sugar or liquid 

packing medium may be determined and certified under the following conditions: 

A. When packed under USDA In-Plant Inspection, with the inspector present to make 

suitable checks verifying the declared fruit-sugar ratio during the entire packing operation 

of the specific lot;

B. When the plant facilities are such that suitable checks can be made during packing 

operations; and 

C. When a sufficient number of checks are made to certify the ratio with a reasonable degree 

of reliability.

Inspectors must determine and verify the proportion of fruit to sugar or liquid sweetener under the 

following circumstances:

D. Whenever the containers are labeled to indicate a specified ratio, and in addition bear 

approved identification marks. The USDA has put its stamp of approval on the product, 

not only for quality but also for fruit-sugar ratio.

E. When an inspector is assigned to plants packing jams (preserves). Frequent checks should 

be made on the raw material to determine the fruit-sugar ratio or proportion of fruit to 

liquid packing media. 

F. Whenever a lot is offered on a government contract requiring that the fruit-sugar ratio be 

determined. 

It is optional for the packer to determine fruit – sugar ratio on containers of less than or equal to 

10 pounds that are not labeled to indicate a specific ratio. 

USDA inspection certificates including the label declaration for fruit-sugar ratio may be 

misinterpreted by the trade to mean that the USDA inspector has verified that declaration, 

particularly if he or she is in-plant during the packing operation. When such verifications are not 

made, the inspection certificate should state that the fruit-sugar ratio was not determined. 
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Even if an applicant does not require a certification of fruit-sugar ratio, inspectors assigned 

to plants should ascertain that the fruit is properly drained, and that there is no 

unreasonable deviation in compliance with the declared or indicated fruit-sugar ratio. 

G. Checks for fruit – sugar ratio under in-plant inspection

Inspection and certification of fruit-sugar ratio should be based upon numerous 

determinations made during processing to allow for reasonable variation between 

individual containers. These are to be expected, even under carefully controlled packing 

conditions. The in-plant inspector should use the method or combination of methods that 

will best work with that particular plant’s processing system. Whenever possible, checks 

should be made by more than one method. 

Checks should start with observing that the fruit or berries are well drained after washing. 

Checks may include: 

1. Physical checks of the amount of fruit, sugar or packing media (or both) 

being packed into individual containers. Procedures will depend upon the 

plant’s operations. 

a. If dry sugar is being used and the fruit and sugar are being weighed 

separately, check the accuracy of the scales or metering devices by 

periodic observations of the weighing operation, and by physically 

weighing the amount of each product being dispensed by such 

devices.

b. If a liquid packing medium is being added, check the actual weight 

of fruit in numerous containers prior to the addition of syrup. 

Determine the proportion of fruit to syrup based on weight of fruit 

in relation to the weight of the entire container.

2. Check of the amount of sugar used and number of containers packed over a 

given interval of time. If the fruit is being mixed with dry sugar in a 

continuous mixer, check the number of containers packed out from a given 

number of bags or other measured quantity of sugar over a reasonable time 

interval. Determine the fruit-sugar ratio based on number of containers 

packed, and quantity of sugar used during that period. Even though there 

will be variation between individual containers, this will represent an 

average value for the entire quantity packed.

3. Checks of the soluble solids. If direct measurements of fruit and sugar 

cannot be made, the ratio can be determined with the soluble solids of both 

the in-going fruit prior to adding sugar, and that of the finished product. 
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See APPENDIX XII for an example of an Optional Worksheet for 

Fruit/Sugar Ratio. 

IN ALL CASES, IT IS IMPORTANT THAT THE INSPECTOR IS ASSURED THAT THE 

FRUIT OR BERRIES ARE PROPERLY DRAINED AFTER WASHING PRIOR TO 

MIXING WITH SUGAR.

H. Estimation based on direct measurement of fruit or packing media in individual containers 

Some plants weigh out a specified quantity of fruit in each container and then add a 

measured amount of sugar or syrup to make up the required net weight. In such instances, 

observe the operation at unannounced intervals and make periodic checks on the weighers. 

Some plants may layer the fruit into the container together with sugar added by means of a 

measured scoop rather than by weight. In such instances, the sugar is generally received 

in 100 pound bags and dumped into a tub or vat located adjacent to the filler. The fruitsugar ratio may be assessed by counting the number of bags of sugar and the number of 

containers packed over a specified interval. For example: 

Over a 5-minute period, 400 pounds of sugar were used in packing 50 containers of fruit 

in 50 pound cans of a specified 5 + 1 ratio. 

 50 cans at 50 pounds each = 2500 pounds finished product. 

 5 + 1 ratio means 5

/6 fruit and 1/6 sugar.

 (1

/6) (2500) = 416 2/3 pounds of sugar. 

Therefore, the packer is complying reasonably close to the declared ratio since the 

theoretical quantity of sugar needed is 416 2/3 pounds, and the packer actually used 

slightly less, or 400 pounds. To look at it from another perspective, 2083 1⁄3 pounds of 

fruit was needed, but 2100 pounds of fruit was used. 

In the case of fruit packed with a liquid packing media, the fruit content can best be 

determined by periodically checking containers prior to the addition of the syrup. 

Generally the fruit is added to the container and then passed beneath a syruper which adds 

a measured quantity of syrup. For example, frozen raspberries packed in 10 pound cans 

with a declared ratio of 4 parts fruit and 1 part syrup would be expected to contain a fruit 

weight of 8 pounds (4/5 x 10) per container.

I. Estimation based on soluble solids 

 The use of soluble solids as a means of estimating the fruit-sugar ratio is not as reliable as 

direct checks on the amount of fruit used in relation to the amount of sugar used. 

However when these direct checks cannot be made, the soluble solids method is probably 

the best alternative procedure. This method does have potential disadvantages: 
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1. It may be difficult to obtain a sample of the finished product that can be positively 

identified as originating from fruit of a specific soluble solids reading. However, if 

the fresh fruit does not vary substantially during the packing period, this error is 

not significant.

2. Numerous samples to determine fruit content must be checked because of the 

variation in the proportion of the fruit and sugar that can be expected from 

container to container.

3. As is true of any method of estimation, excess water adhering to the berries after 

washing will lower the Brix value of the finished product, and tend to distort the 

true fruit-sugar ratio. When water is calculated as part of the fruit component, the 

results indicate more fruit content than was actually provided. 

Despite the potential for error, the ratio of fruit to sugar may be estimated with a 

reasonable degree of accuracy. The more samples taken throughout the day, the 

more the average ratio obtained will compensate for errors in individual samples. 

Follow this procedure: 

a. Obtain a representative one-pound sample of the in-going fruit before 

processing. If the fruit is washed, select the sample immediately before

mixing with the sugar. Do not drain the sample any more than is normally 

accomplished during processing. 

b. At approximately the same time, obtain a sample of the finished product 

prior to freezing. This sample should be selected and prepared as follows: 

(1) If retail size containers, select a sufficient number simultaneously 

from the line to make an approximate 2 pound composite (e.g. three 

10-ounce cartons or two 16-ounce cartons).

(2) If institutional size (e.g. No. 10 cans), thoroughly mix the entire 

container and select a representative 3 pound subsample. 

(3) If bulk containers, such as 30 pound cans or barrels, catch 

approximately 15 pounds from the filler, mix thoroughly, and select 

a representative 3 pound subsample. This method can only be used 

with continuous or pre-mixing filling operations, not independent 

or layered fill.

c. Place the finished product sample above in a blender or other mechanical 

mixer, and comminute until it is thoroughly mixed and homogeneous. 
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d. Place a drop of the filtrate from this comminuted mixture (filtered through 

a rapid filter paper if needed) on the refractometer prism, and determine the 

Brix reading. Make any necessary temperature correction. 

e. Follow steps 3 and 4 above to determine the soluble solids of the in-going 

fruit obtained before mixing with sugar. 

f. Knowing the soluble solids of both the in-going fruit and the finished 

product, calculate the proportion of fruit to sugar as follows: 

R = 100 - Ps in which 

Ps - Fs

R = Ratio of fruit to sugar. 

Ps = Soluble solids of finished product (fruit plus sugar). 

Fs = Soluble solids of in-going fruit. 

Example:

The soluble solids of fresh peaches is 12.2. The soluble solids of the 

finished product (peaches plus dry sugar) is 31.8. 

 The fruit-sugar ratio is calculated as follows:

R = 100 - 31.8 

31.8 - 12.2 

R = 68.2 

19.6 

R = 3.48 

If the product were labeled or specified as a 3.5 to 1 ratio, the actual proportion of 

fruit to sugar (3.48 to 1) would meet requirements.

J. Ratio determination frequency guidelines (in plant) 

If the fruit and sugar (or liquid sweetener) are being weighed or metered into individual 

containers, the inspector should check samples for accuracy at approximate hourly 

intervals for each line. If the results remain satisfactory, this frequency should be 

adequate. 

If the fruit and sugar are being mixed in a continuous type mixer and the determination is 

based on soluble solids, samples of the fresh fruit should be checked at approximate 
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hourly intervals. 

Samples of finished product should be checked according to the following schedule:

 First 8,000 pounds 3 

 Each additional 8,000 pounds 1 

For example, if a line is capable of producing 10,000 pounds per hour for an 8-hour shift 

(80,000 lbs), check 3 samples for the first 8,000 pounds, and check 9 samples during 

production of the next 72,000 pounds, for a total of 12 samples for the shift. 

These are minimum sampling rates and should be increased if warranted. Keep in mind 

that the more frequent the checks, the more reliable the lot estimate.

Verification of Fruit – Sugar Ratio: Lot Inspection

As a general rule, fruit-sugar ratio will not be determined or certified under lot inspection. Fruitsugar ratio results based solely on the finished product are not fully reliable. However, if 

specifically requested by the applicant, the ratio may be estimated as follows:

 

A. If the lot can be identified as having been packed under In-Plant Inspection, the fruit-sugar 

ratio may be certified, if the records compiled at time of packing substantiate the declared 

ratio. See the section on In Plant Inspection for key measurements for ratio determination. 

Information may be obtained from the SCI Division field office involved. 

B. If there is no history on the lot, the fruit-sugar ratio can be estimated using the average 

natural solids for the specific fruit. The reliability of this testing depends upon the degree 

to which the in-going fruit conforms to average values established for that fruit, as well as 

the integrity of the packer in observing good commercial practice during processing. 

Certification will be restricted to finished product examination only. 

Particularly for retail packs, some buyers base their specifications on finished soluble solids and 

not on a specified ratio. For example, the buyer's specification may indicate that the finished 

product solids must be in the range 25 to 28 degrees Brix. In these instances, determine the solids 

and report the findings in terms of soluble solids with no conversion to fruit-sugar ratio.

If the applicant requests a fruit-sugar ratio on the finished product, the most reliable means of 

checking the fruit content is by measuring the soluble solids. See In Plant Inspection., Estimation 

based on soluble solids for the procedure and formula used for calculating the theoretical fruitsugar ratio. Under these circumstances, a figure representing the average solids of the fresh fruit 

is substituted for the soluble solids of in-going fruit, since the actual solids of the in-going fruit is 

unknown. 

This procedure involves comminuting the entire container for the solids test, and checking a 
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representative number of containers to estimate the ratio with reasonable accuracy. The applicant 

should be informed ahead of time that full containers must be taken for the test, and the inspection 

will be lengthy due to the time it takes to prepare the samples.

C. The "authentic values" referred to in this section are based on Food and Drug data 

prepared by examining numerous samples of the respective fruits or berries, and is 

summarized in the Journal of the AOAC, Vol. XXI, No. 3, August 1938. 

Average Authentic Values for the Most Common Fruits and Berries

Apples 13.7 

Apricots 14.4 

Blackberries 10.0 

Cherries 13.9 

Crabapples 15.4 

Currants 10.6 

Figs 19.0 

Gooseberries 8.2 

Guavas 7.6 

Loganberries 10.6 

Grapes 14.1 

Peaches 11.8 

Pineapples 14.6 

Plums 14.8 

Raspberries (red) 10.5 

Raspberries (black) 11.2 

Strawberries 8.0 

Example of calculation for frozen strawberries:

Ps (soluble solids of product) = 28.4 

Fs (soluble solids of authentic fruit) = 8.0 

R = 100 - 28.4 

 28.4 - 8.0 

R = 71.6 or 3.50

 20.4 

1. There are limitations and potential errors in using soluble solids as an estimation of 

fruit content: 

a. The entire contents of container must be comminuted, leading to 

destruction of the product. In addition, this can be time consuming 

especially in the case of bulk containers.
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b. If the fresh fruit varies materially from the established authentic 

values, results will be questionable. 

c. Improper draining of washed fruit, or the addition of water 

materially affects the ratio. This is a very significant factor, as 

shown by the following example. 

Assume a processor is packing strawberries to a declared ratio of 

4 + 1, that the strawberries have a soluble solids of 8.0 percent, and 

that for each 100 pounds of finished product, 8 pounds of water is 

unintentionally added through improper draining. 

(1) For each 100 pounds there should be 80 pounds of berries 

and 20 pounds of dry sugar. 

 80 lbs. fruit at 8 percent solids = 6.4 lbs 

20 lbs. sugar at 100 percent solids = 20.0 lbs 

Theoretical solids of finished product = 26.4 lbs. 

 Applying the formula in Section B., Estimation based on soluble 

 solids, this ratio is: 100 – 26.4 or 73.6 or 4.0:1

 26.4 – 8 18.4 

(2) However there will actually be 72 pounds of berries, 8 

pounds of water, and 20 pounds of dry sugar. 

72 lbs. fruit at 8 percent solids = 5.76 lbs 

8 lbs. water at 0 solids = 0 lbs 

20 lbs. sugar at 100 percent solids = 20 lbs 

Finished productsolids = 25.76 lbs. 

Rounding up and applying the formula as above, this ratio is: 

 100 – 25.8 or 74.2 or 4.2:1

 25.8 – 8 17.8 

From the soluble solids values, this makes it appear that the packer is being 

generous with the fruit, while he has actually substituted 8 pounds of water 

for 8 pounds of fruit. This illustrates the importance of checking that the 

fruits used in processing are properly drained. 

D. Ratio determination frequency guidelines (lot inspection) 
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If an estimate is required on lot inspection and there is no previous history of the lot, entire 

containers must be checked. For lots of 20,000 pounds or less, make a minimum of 6 

determinations. For lots in excess of 20,000 pounds, make a minimum of 13 

determinations. If the lot is very large, increase the number of determinations at the rate 

of 6 for each approximate 50,000 pounds in excess of 100,000 pounds. 

In the case of large containers, this sampling rate may appear rather high. However, it is 

necessary to assure a reliable estimate.

Determining Lot Acceptance

Depending upon the product and packing practices, a reasonable deviation in fruit-sugar ratio 

between individual containers is to be expected. Lot acceptance is based on the average value of 

numerous ratio determinations. However, there is also a limit on individual sample deviation. To 

be in compliance with the declared or specified ratio, the following criteria must be met. 

A. For the average of all samples, allow a tolerance of 0.2 ratio below declared or specified 

ratio, and 0.2 ratio above declared or specified ratio. 

B. All individual determinations must be within the range of plus or minus 4 degrees of the 

soluble solids value corresponding to the declared or specified ratio, except: 

1. Individual checks that exceed the 4 degrees limitation is allowed at a tolerance 

equal to the deviant rate (1 in 6, 2 in 13, etc), provided: 

(a) No individual determination is more than plus or minus 8 degrees of the 

soluble solids value corresponding to the specified ratio. 

Example: Frozen Strawberries packed to a 4 plus 1 ratio, fresh fruit solids of 8 

percent. The theoretical solids of the finished product of a 4 + 1 ratio 

should be 26.4. 

• the average of all the determinations must be not less than 3.8 nor 

more than 4.2 (4 ± .2 for the ratio); 

• no more than 1 in 6, 2 in 13, etc. may be less than 22.4 degrees nor 

more than 30.4 degrees soluble solids (26.4 ± 4 degrees); and 

• no individual may be less than 18.4 degrees nor more than 34.4 

degrees soluble solids (26.4 ± 8 degrees). 

These guides are intended to allow for reasonable variations under normal packing 

procedures. For products that are closely controlled by direct measurement, this

allowance for individual samples may seem rather liberal. However, in the case of 

products like frozen strawberries, experience has shown that a reasonable tolerance must 

be permitted. This doesn’t mean that packers should be permitted to continually fall 
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below requirements or take advantage of the administrative guides outlined above. If the 

inspector finds that the plant has a tendency to be slightly low on the amount of fruit used 

relative to sugar or packing medium, this deviation should immediately be called to the 

attention of plant management for correction. 

GOOD COMMERCIAL PRACTICES

Counts 

Unless otherwise specified, when either a count range or a specific count (even if qualified by the 

word "approximately") is declared on a label or specified by a purchaser, criteria for "good 

commercial practice" shall apply. 

A lot will be considered as complying with requirements of good commercial practice under the 

following conditions: 

• Average of all sample units meet the declared or required count; and

• Fifty percent or more of the sample units meet or exceed the declared or required count. 

Range of Counts Guide for Good Commercial Practice 

A. When a range of counts is specified or declared, counts in all sample units must fall within 

this range. Sample units with counts not falling in this range are allowed as deviants as 

specified in the Regulations (in addition to quality deviants), provided these counts do not 

exceed the limits outlined below.

1. Sliced Pineapple

a. Counts up to 20 Slices or 40 half Slices

Allow 1 slice or 2 half slices less than the lower end of the range, or more 

than the upper end of the range. 

b. Counts Over 20 Slices or 40 Half Slices 

Allow 5 percent by count less than the lower end of the range, or more than 

the upper end of the range.

2. Other Processed Products 

a. Counts up to 20 Units 

Allow 2 units less than the lower end of the range, or more than the upper 

end of the range.
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b. Counts over 20 Units 

Allow 10 percent by count less than the lower end of the range, or more 

than the upper end of the range. 

Specific Count Guide for Good Commercial Practice 

A. When a specific count is declared or specified, count in sample units may vary above and 

below this number within the limits shown below. Sample units with counts that deviate 

from these limits are considered deviants (in addition to quality deviants) as specified in 

the Regulations. If the deviation is considered excessive for current packaging practices, 

then a 1 in 48 allowance should be applied. 

1. Sliced Pineapple

a. Counts up to 20 Slices or 40 Half Slices 

Allow 1 slice or 2 half slices less than the specific count. 

Allow 2 slices or 4 half slices more than the specific count. 

b. Counts over 20 Slices or 40 Half Slices 

Allow 5 percent by count less than the specific count. 

Allow 10 percent by count more than the specific count. 

2. Other Processed Products 

a. Counts up to 20 Units 

Allow 1 whole or half unit less than the specific count. 

Allow 2 whole or half units more than the specific count. 

b. Counts Over 20 Units 

Allow 5 percent by count less than the specific count. 

Allow 10 percent by count more than the specific count.

DRAINED WEIGHT 

Although generally not a factor of quality, drained weight of processed fruit and vegetable 

products is an important marketing consideration. It indicates the amount of fruit or vegetable 

ingredient in relation to packing media, and sometimes the degree to which a product may have 

disintegrated during processing and handling. 

A. Drained weight considerations: 
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1. Most U.S. standards for canned fruits and vegetables contain a recommended

drained weight consistent with good commercial practice;

2. Drained weight can be a requirement in purchase specifications (i.e., USDA 

Commodity Specifications); 

3. Drained weight may be a requirement in a buyer-seller contract; 

4. Drained weight is a limiting quality factor in Canned Tomatoes; 

5. Drained weight is a Food and Drug mandatory requirement in the standard of fill 

for Canned Fruit Cocktail, Mushrooms, Canned Tomatoes, and Canned Crushed 

Pineapple;

6. Drained weight is the common labeled statement of contents for a few products, 

such as Canned Olives and Canned Mushrooms; and 

7. Drained weight requirements or recommendations may vary for the same product 

in the following cases:

a. Maturity - as in Canned Whole Kernel Corn 

b. Count - as in Canned Pears and Canned Plums 

c. Size of units - as in Canned Green and Wax Beans 

Limits of Good Commercial Practice

Unless specified in the U.S. Standards for Grades or other inspection documents, compliance with 

the minimum drained weight recommendations will be determined by the following criteria.

• The average of all sample units in the lot must meet the minimum; and 

• There shall be no unreasonable shortage in any individual container. 

Determination of "Unreasonable Shortage" 

Unless specifically covered by an inspector’s instruction or a U.S. standard, the following 

administrative guide applies to all canned fruit and vegetable products. The drained weight of no 

container may be as follows, whichever is the lesser drained weight. 

• Less than 45% of the container’s water capacity, or

• More than the weight of one average size unit of product below the recommended or 

required minimum 
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Averaging Drained Weights of Codes within a Lot 

Drained weight averages for individual codes, shifts, or portions of shifts in a lot may be less than 

the required minimum average but may not be unreasonably low. Averages failing the criteria 

below are considered unreasonably low. 

A. Limits for low average drained weights: 

1. No. 2 1⁄2 can size and smaller

95% of the minimum requirement or 0.5 ounces low, whichever is the lesser 

weight.

2. Containers larger than No. 2 1⁄2 can size 

97% of minimum requirement or 1.0 ounce low, whichever is the lesser weight. 

Procedures for Frozen Products In-Plant or Lot Inspection

A. Drained weight is not taken routinely on frozen food. However, it may be determined 

upon request of the applicant, and it should be taken where there is evidence that the 

product may contain excessive ice.

1. Retail Packages

After obtaining gross weights, allow containers to thaw at room temperature 

(approximately 70 oF), or immerse the packages in water circulated and maintained 

at 68 oF plus or minus one degree. If packages are not watertight, place in a 

suitable plastic bag, remove as much excess air as possible and tie off. Avoid 

agitation of packages during thawing by using clamps or weights if necessary. 

When the center of package reaches approximately 30 o

F, remove from bath, blot 

off adhering water, and open with minimum agitation. 

Tare a No. 8 mesh sieve. Use an 8-inch diameter sieve if the container holds 16 

ounces or less, and a 12 inch sieve if more than 16 ounces. With the screen tilted 

about 21⁄2 inches and supported for drainage, distribute the contents of the package 

evenly over the screen in one sweeping motion. Drain for exactly two minutes, 

reversing the tilt of the screen after one minute.

2. Bulk Containers (principally fruits)

After obtaining gross weights, allow the unopened containers to thaw at room 

temperature (approximately 70 o

F) until the product temperature in the center of 

the container is approximately 30 oF.
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Divide the thawed samples into four or more aliquots with each increment not to 

exceed 8 pounds and drain two minutes on a tilted 12 inch No. 8 mesh sieve, 

reversing the tilt of the screen after one minute. The combined weight of the four 

or more aliquots is the drained weight of the product. 

Do not allow center temperatures to exceed 40oF prior to determining drained 

weights on retail or bulk containers.

3. In-line Control 

a. Sampling

Subgroups of 3 may be taken every 30 minutes to provide a good in-line 

control on fill. The subgroups are drawn prior to freezing at a point where 

no further change in the net weight is likely to occur. 

b. Tare

Tare weights should be determined as outlined in the AIM Inspection 

Series, General Procedures Manual. 

c. Net Weights

Net weights should be determined as outlined in the AIM Inspection Series, 

General Procedures Manual. Immediately after the subgroup has been 

drawn, determine the net weight of each of the 3 sample units. They may 

be recorded on a XX� Data Sheet similar to the example on page 144. 

d. Drained Weights

Drained weights are determined as follows and may be recorded on a XX�

Data Sheet.

(1) Tare a No. 8 mesh sieve appropriately sized for the container. 

(2) With the screen tilted about 21⁄2 inches and supported for drainage, 

distribute the contents of the package evenly over the screen in one 

sweeping motion. 

(3) Drain for exactly two minutes, reversing the tilt of the screen after 

one minute to release any water that may be on the flange. 

(4) The weight of the sieve and product minus the weight of the dry 

sieve is the drained weight. 
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(5) The subgroup average of the net weights minus the subgroup 

average of the drained weights is the subgroup average of the 

weight of water.

e. Calculations 

All calculations are to be made to the nearest 0.1 ounce. Calculate 

XX� (subgroup average) separately for the net weights and drained weights. 

These values may be recorded on the XX� Data Sheet opposite XX�. 

Determine XX� for the weight of water for each subgroup by subtracting the 

drained weight subgroup average from the net weight subgroup average. 

This value may also be recorded on the XX� Data Sheet opposite XX� (wt. of 

water).

At the end of each shift or production day run, calculate XX� for drained 

weights and XX� for weight of water by adding the approximate XX� values and 

dividing by the number of XX� values. If using the XX� Data Sheet, record these 

XX� values in the upper right-hand corner of the sheet.

f. Plotting

The XX� values (individual drained weight values) and the XX� values for 

drained weights representing each subgroup are plotted on the upper 

portion of a control chart. The XX� values for the weight of water are plotted 

on the lower portion of the control chart. 

g. Limits 

Warning limits and reject limits will vary with the product. 

4. Limitations

These instructions will not apply to products for which special procedures have 

been developed. An example is the inspection of Strawberries under the State of 

California Marketing Order. 
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Example of a Statistical Weight Log:
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FILL OF CONTAINER

Despite label statements concerning the weight or volume of a product in a container, purchasers 

may be misled as to the amount of the commodity they are buying. The Food and Drug 

Administration (FDA) requires that food containers be filled as full as is practical without 

impairment of quality. Section 403 (d), of the Federal Food, Drug and Cosmetic Act (21 U.S.C. 

343) (which may be found at the following internet address: https://www.ecfr.gov/cgibin/ECFR?page=browse) states that "a food shall be deemed to be misbranded if its container is 

made, formed or filled as to be misleading."

There is no single criterion that can be generally applied to all processed food products in 

determining proper fill. Factors which either singly or in combination may indicate improperly 

filled containers include: 

1. Low net weight or contents. 

2. Excessive headspace.

3. Low drained weight. 

4. Insufficient packing medium.

5. Insufficient fruit or vegetable ingredient in relation to packing medium. 

6. Container size considerably larger than actual contents of product therein. 

Criteria for Determining "Fill of Container"

A. Consideration must be given to certain mandatory requirements by FDA, or fill 

recommendations included in U.S. Standards for Grades in certifying the "fill of 

container” for products as outlined below: 

1. FDA Mandatory Requirements 

Legal standards for "Fill of Container" have been published by the FDA for the 

following specific processed food products: 

Canned Applesauce

Canned Apricots 

Canned Cherries

Canned Cream-Style Corn

Canned Crushed Pineapple 

Canned Fruit Cocktail 

Canned Grapefruit

Canned Mushrooms 

Canned Peaches
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Canned Pears

Canned Peas

Canned Pineapple Juice 

Canned Tomatoes 

Note that this list is not to be considered all inclusive, and other products may be 

added from time to time.

The criteria and method of determining compliance with these "fill of container" 

requirements vary for each product. Please review the following examples: 

a. Containers filled as full as practicable without impairment of quality.

Examples: Canned Apricots Canned Peaches

Canned Cherries Canned Pears

b. Total weight of drained fruit (or vegetables) not less than a required 

percentage of the water capacity of the container.

Examples: Canned Fruit Cocktail Canned Mushrooms 

Canned Grapefruit Canned Ripe Olives 

c. When removed from the container and returned in a specified manner, the 

vegetable ingredient completely fills the container.

Example: Canned Peas

d. A fill of not less than 90 percent of the total capacity of the container. 

Examples: Applesauce, Cream-Style Corn, Crushed Pineapple, 

Pineapple Juice, and Canned Tomatoes. 1/ 

e. All products not specifically covered by a "standard of fill" must 

comply with the requirements of the Federal Food, Drug and Cosmetic 

Act (FD&C Act) with respect to deceptive fill. In other words, the 

containers must be filled to the extent that the consumer is not deceived by 

the size of the primary container in relation to the actual amount of product. 

1/ In glass with a capacity of 61⁄2 fluid ounces or less, the fill is not less than 85 percent. 

The following examples illustrate "deceptive fill."

(1) Actual contents considerably less than the capacity of the container.

Examples: Potato Flakes in which substantially less than 90 percent of the 
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capacity of the container consists of product, or 

Frozen Spinach in which the capacity of the carton is substantially 

greater than the volume of spinach in the carton. 

(2) Noticeable deficiency of fruit and vegetable ingredient in relation to 

total contents of container (including packing medium). 

Example: Canned Blackberries in which the drained weight of berries is 

extremely low (less than 50 percent of the water capacity of the 

can) even though the can is well filled with berries and packing 

medium.

2. Recommendations or Requirements of U.S. Standards for Grades 

a. Canned Fruits and Vegetables 

(1) FDA Standards of Fill for specific commodities becomes a 

requirement of the U.S. Standards for Grades. 

Example: Those commodities listed in A.1. for which the FDA has published 

"Standards of Fill." 

(2) In some cases, the U.S. Standards for Grades recommend: 

(a) “Fill of not less than 90 percent of the capacity of 

container.” 

Example: Canned Applesauce, Canned Beets.

(b) “As full as practical without impairment of quality.”

(3) If not specifically mentioned in the U.S. Standards for Grades, fill 

of container must meet the mandatory requirements of FDA with 

respect to deceptive fill. 

b. Frozen Fruits and Vegetables and Miscellaneous Products (other than 

canned).

(1) Currently there are no FDA "Standards of Fill" for specific frozen 

fruits, vegetables, or for certain canned fruits and vegetables.

(2) The U.S. Standards for Grades do not include recommended fill of 

container for all commodities. However, Division policy requires 

that all products comply with the FD&C Act with respect to 
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deceptive fill.

(a) Recommendation in U.S. grade standard. 

Example: Frozen Concentrated Sweetened Grape Juice - "as full as practical 

without impairment of quality." 

(b) No recommendation in U.S. grade standard. 

Examples: Frozen Spinach, Frozen Cauliflower, Frozen Berries, and most 

frozen products - proper fill implied by the mandatory requirements 

of the FD&C Act with respect to deceptive fill.

3. Guide for "Good Commercial Practice"

Because "fill of container" is so closely associated with other factors such as net 

weight, drained weight, and headspace, any administrative guides applicable to 

these factors must also be considered in dealing with fill of container. Inspectors 

should observe the following procedure to determine reasonable deviation within 

the limits of good commercial practice: 

a. If the product is fluid or homogenous in nature (juice, puree, jams, and 

jellies) and headspace measurements are an index of properly filled 

containers, allow the same number of containers to exceed headspace 

requirements as are allowed for deviations in quality per sampling plans 

contained in the Regulations. No limit is being suggested as to what extent 

individual samples may exceed maximum headspace measurements, since 

extreme deviations will be reflected in net weight or content 

determinations.

b. Frozen Fruits and Vegetables. Sufficient data has not been accumulated to 

finalize a guide for good commercial practice. However, if the product 

does not occupy at least 50 percent of the capacity of the container, the 

certificate should reflect this. 

The percent fill of a container is determined by the following calculation:

Volume of product in container 

 Total capacity of container 

Example: Frozen Spinach - capacity of carton 125 cu. in. 

 Volume of Spinach, by displacement, 60 cu. in. 

 60 

 125 

In this instance, the container is not well filled and the Grade Statement 

x 100 = Percent Fill

x 100 = 48 Percent Fill
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should be properly flagged to direct attention to the "Fill of Container" in 

the body of the certificate. (See the AIM Inspection Series Certification 

Manual.) 

If the product occupies more than 50 percent but less than 75 percent of the 

container capacity, the fill would be questionable and should be reported in 

the body of the certificate, but the Grade Statement would not be flagged. 

NET WEIGHT

Fresh Products 

Refer to the Net Weight section of the General Market Manual for guidelines and procedures for 

determining net weight of fresh products. 

Processed Products 

Processed foods are commonly packed to meet a prescribed net weight or content and labeled 

accordingly. This net weight or content may be specified in a purchase specification or contract.

In the case of canned foods, if the containers are unlabeled and the required net weight or content 

is not stipulated in the purchase specification or contract, be guided by statements on labels 

customarily used for the commodity and container size. 

Various guidelines have been developed for net weight and other measures of content. However,

no specific reference is usually made to samples that contain an excessive quantity of product. 

Overfill may be undesirable for its effect upon vacuum, adequate sterilization of product under 

normal processing times and temperatures, or possible strain on container during retorting or 

processing. The Division is not in position to recommend maximum filling guides, but inspectors 

should review specifications with an eye for any specifications concerning over fill and under fill.

Net weights are not a factor of grade. However, compliance with the required net weight or 

volume is very important from an economic and regulatory viewpoint. The packer or other 

person responsible for shipping a product in interstate commerce is responsible for the accuracy 

and completeness of labels. Some buyers refuse to accept deliveries of processed products which 

contain more than a small percentage of short weight or short volume containers.

To avoid being considered mislabeled in accordance with the provisions of Section 403 of the 

Federal Food, Drug and Cosmetic Act, (which may be found at the following internet address: 

https://www.ecfr.gov/cgi-bin/ECFR?page=browse) a packaged food must meet the following 

criteria.

"It bears a label containing an accurate statement of the quantity of the contents in terms of 

weight, measure, or numerical count; provided that reasonable variations shall be permitted, and 

exemptions as to small packages shall be established, by regulations prescribed by the 
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Administrator."

The Act further provides that: 

"The statement shall express the minimum quantity, or the average quantity, of the contents of the 

packages. If the statement is not so qualified as to show definitely that the quantity expressed is 

the minimum quantity, the statement shall be considered to express the average quantity." 

Where the statement expresses "minimum quantity", no deviation below such declared minimum 

is permitted.

Where the statement expresses "average quantity":

• Variations are permitted when caused by unavoidable deviations in weighing or measuring 

which occur in good packing practices, except that such variations shall not be permitted 

to the extent that the average weight or measure of the packages in the shipment is below 

the quantity declared on the label and, 

• No unreasonable shortage in any package is permitted, even though other packages in the 

same shipment compensate for such shortage. 

Guide for "Good Commercial Practice"

A. A lot will be considered to comply with requirements of "good commercial practices" with 

respect to average net weight or other measure of contents under the following conditions: 

1. The average of all containers meets the declared, required or recommended 

minimum; and

2. No container may be less than the tolerance specified in the following applicable 

groups: 

a. Canned and Frozen Fruits and Vegetables 

(1) Containers of 10 ounces or less: 10% or 0.5 ounce, whichever is 

less.

(2) Containers over 10 ounces up to 50 ounces: 5% or 1 ounce, 

whichever is less.

(3) Containers over 50 ounces: 2% or 2 ounces, whichever is less. 

Example: 10 ounce Frozen Vegetable carton 

(a) The sample average must be at least 10.0 ounces. 

(b) No container in the sample may weigh less than 9.5 ounces. 
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The 0.5 ounce allowance is less than 10% of 10 ounces (1.0 

ounce). 

3. Canned and Frozen Concentrated Fruit or Vegetable Products 

a. Containers of 8 ounces or less: 5% or 0.2 ounce, whichever is less. 

b. Containers over 8 ounces up to 50 ounces: 2% or 0.5 ounces, whichever is 

less.

c. Containers over 50 ounces: 2% or 1.5 ounces, whichever is less. 

Example: Tomato Paste in No. 10 cans, declared net weight 112 ounces 

(1) The sample average must be at least 112 ounces.

(2) No container may weigh less than 110.5 ounces. The 1.5 ounces 

allowance is less than 2 percent of 112 ounces (2.24 ounces). 

4. Miscellaneous Processed Products

Such as Jams and Jellies, Peanut Butter, Spices, Flavoring Extracts, and Similar 

Products 

a. Containers of 8 ounces or less: 10% or 0.3 ounces, whichever is less. 

b. Containers over 8 ounces up to 50 ounces: 5% or 0.8 ounces, whichever is 

less.

c. Containers over 50 ounces: 2% or 1.5 ounces, whichever is less. 

Example: Fruit Jelly in 12 ounce jars 

(1) The sample average must be at least 12.0 ounces. 

(2) No container in the sample may weigh less than 11.4 ounces. 5% of 

12 ounces (0.6 ounces) is less than the 0.8 ounce allowance. 

In applying the guides, consider the allowance relative to sample size. Obviously, the tolerance 

of a "defective" or low net weight sample unit in a sample size of 6 is not the same as a 

"defective" in a sample size of 29. Consideration should be given to permitting an infrequent 

container to deviate beyond the range of good commercial practice. At the applicant’s request, 

you may check additional samples from the lot, and allow low net weights at a rate of 1 in 48. 
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VACUUM READINGS

The term “vacuum,” as used in the canning industry represents the difference between 

atmospheric pressure and lower pressure existing in a closed container. Atmospheric pressure 

decreases with an increase in altitude at the rate of approximately 1 inch of mercury for each 

1,000 feet. Consequently, a container having a reading of 7 inches of mercury at sea level would 

have only 2 inches of mercury in Denver (elevation 5,000 feet). Although pressure may be 

recorded using different units of measure, one of the most common units of measure for vacuum 

gauges is inches of mercury. This refers to the height of a column of mercury in a U-Shaped tube 

(manometer) that may be supported by that pressure. 

Temperature also affects vacuum readings. There is a relationship between the temperature at 

which the container is closed and sealed, and the vacuum of the container after processing and 

cooling. There is also a relationship between the vacuum readings of sealed containers at various 

temperatures. Studies have shown that the vacuum decrease is approximately 1 inch of mercury 

for each 5 degrees Celsius © increase in temperature. Thus, a container having a vacuum of 5 

inches of mercury at 20 degrees C would have zero (0) at 45 degrees C. Prolonged storage at 

higher temperatures of such merchandise could result in “flippers” or “swells.” 

Although there are several methods by which “vacuum” may be measured in canned food 

products, the conventional method of using a mechanical gauge calibrated against a mercury 

volume has been adopted by the Division. As discussed here, vacuum readings refer to those 

readings as determined by a conventional vacuum gauge, and are expressed in inches. 

Cans should be at approximately room temperature before vacuums are taken. The correct 

technique for taking a vacuum reading is to force the tip of the vacuum gauge into the can at a 

high spot near the closing machine seam. This high spot is selected to minimize the chance of the 

gauge tip entering the product, plugging the gauge and obstructing a vacuum reading. Take care 

not to bang the gauge, which may dull the tip and damage the gauge. There may be some slight 

variation to the technique for specific products or can sizes; be guided by your supervisor. 

Vacuum is not a factor of grade but may be a requirement of a purchase specification or contract. 

Inspectors must be alert for specific vacuum requirements in such orders. 

The general requirement “packed in accordance with good commercial practice” which appears in 

most government specifications is interpreted as requiring vacuum on those products that are 

customarily packed so as to have a vacuum. The amount of vacuum in a can depends on many 

factors – product, container size, the particular process, temperature, and altitude. No attempt 

should be made to evaluate the readings except as directed in this instruction, or inspector’s 

instructions for a specific commodity. 

Guide for Good Commercial Practice

A. Consideration must be given to the type of product, type of container, special contractual 

requirements, and existing commercial practices. 
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1. Containers with screw cap closures or friction type lids may not be designed to 

maintain vacuums. Consequently zero vacuum reading in such containers may be 

considered acceptable under good commercial practices. 

2. Zero vacuum readings are considered less serious in products of the acid group 

(pH of 4.5 or less) than for those in the non-acid group (pH in excess of 4.5). 

Acid Group

Apples 

Apricots 

Berries

Cherries

Citrus Products 

Peaches

Pears

Pickles

Plums

Prunes 

Sauerkraut

Tomatoes

Non-Acid Group

Asparagus 

Beets

Black-eyed and Field Peas

Canned Dried Beans 

Carrots 

Corn

Green and Wax Beans

Hominy

Lima Beans

Okra

Peas

Pimientos

Zero vacuum readings in containers which normally have a vacuum are recorded and 

certified according to the AIM Inspection Series, Certification Manual. If a contract or 

specification includes specific minimum acceptance levels for vacuum readings, these 

requirements must be taken into consideration when certifying the lot. 

B. In the absence of a contractual or program requirement for zero vacuums, inspectors will 

be guided by the following for both commercial and government contracts. 

1. Acid group 

Allow 10 percent of the sample units to have zero vacuum readings before flagging 

the inspection certificate.

2. Non-acid group

Allow only those samples units to have zero vacuum readings as can be considered 

infrequent (1 in 48). 

Vacuum Requirements

If a specification or contractual document does not specify or designate a vacuum in terms of a 

measurable determination, but simply states that the cans shall have a vacuum, any vacuum 

reading above zero is considered to meet these requirements. Unless the needle is influenced by a 

disturbance such as jarring, any movement of the vacuum gauge needle above zero is considered 
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evidence of a vacuum and therefore complies with the requirements. 

Where the specification or contractual document specifies a minimum vacuum, the permitted 

number of sample units that fail the requirement shall be as indicated in Contract Services Section 

instructions in the Inspections for Operational Rations Purchased by the Department of Defense 

Manual for DPSC deliveries, and in AIM Inspection Series, Sampling Manual for all other 

inspections. 

When the vacuum indicates a vacuum of between 0 and 1 inch, record the vacuum as 1 inch on 

the score or tally sheet. Any other fractional vacuum reading above 1 inch will be rounded down 

and the vacuum recorded as a whole number. For example, a reading of 4 1⁄2 inches on the 

vacuum gauge will be recorded as 4 inches.

MACROANALYTICAL PROCEDURES

"Macroscopic" analysis of a product refers to an evaluation of the substance through the use of a 

person’s unaided senses, primarily sight, smell, or taste. Probably every consumer in our society 

conducts some form of macroscopic examination to check for defects when purchasing or using 

foods and other consumer goods. The examination may range from a cursory or even 

unconscious visual check of the product to confirm that everything "looks right" to a much more 

detailed scrutiny to check for specific defects. A typical example of consumer macroscopic 

examination would be the shopper seen squeezing and sniffing the produce prior to purchasing. 

In fulfilling responsibilities for protecting the public health and safety, regulatory authorities 

conduct more systematic examinations to detect both apparent and hidden defects. Over the 

years, standardized methods of macroscopic examination have evolved for determining filth, 

decomposition, and foreign matter in foods, drugs, and cosmetics and other products subject to 

the laws enforced by the U.S. Food and Drug Administration (FDA). These methods of analysis 

have evolved with the input of producers and consumers as well as regulatory authorities. 

The FDA Macroanalytical Procedures Manual is available at the following website: 

https://www.fda.gov/food/laboratory-methods-food/macroanalytical-procedures-manual-mpm

For inspectors without internet access, please contact your immediate supervisor as needed for a 

copy of this manual. 

SALT DETERMINATION

This section in the Technical Manual is intended for use by inspectors and focuses on procedures 

for determining salt content in food products. Slight deviations in preparatory procedures are 

sometimes necessary for a particular commodity; be guided by the grading manuals for the 

product as needed. 

SAFETY WARNING: Silver Nitrate (AgNO3) solutions are used in titrations for salt 

determination. Dilute (0.1 N) AgNO3 is not corrosive (although it will discolor the skin on 
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contact), however, it may be necessary to work with concentrated or crystalline AgNO3 to prepare 

the reagent. Both forms are extremely caustic and must be handled with great care. Wear 

protective clothing, eye wear and gloves so that it cannot contact your skin or eyes. Work only in 

an adequately ventilated room, or under a ventilated hood to avoid vapor inhalation. If you 

accidentally come in direct contact with either form of AgNO3, immediately wash the area with 

running water for several minutes. 

Be equally cautious when handling concentrated Nitric Acid. If it should contact your skin, 

quickly cover the area with large amounts of sodium bicarbonate or wash with running water. 

See the AIM Inspection Series, Sanitation and Safety Manual for more information concerning 

the safe handling of corrosive chemicals. See also the Material Safety Data Sheets (MSDS) for 

these chemicals.

Glassware and Equipment

AgNO3 solution will cause staining with a dark residue that is extremely difficult to remove from 

glassware. Wash flasks and beakers immediately after each titration or use. It is not practical to 

wash a burette after each test or between a series of titrations; however, a thorough washing at the 

end of each day will help to keep staining to a minimum.

Terminology 

"Salt" as used in this instruction and in most food standards means "common salt" or sodium 

chloride (NaCl). It is also customarily referred to as "table salt" although table salt generally 

contains a few additives and is not chemically pure. 

In this instruction, the total chloride content (i.e., that which occurs naturally, plus any added by 

the processor) is determined and results are expressed in terms of sodium chloride. These results 

frequently include several other chloride salts such as potassium chloride and calcium chloride. 

However, these other salts are usually present in extremely small quantities and are considered 

insignificant. 

Methodology and Reagents 

A. The most common methods for determining the salt content of food products involve 

titration, either with a visual indicator or by potentiometer. These methods include: 

1. Visual Indicator Method 

(a) Mohr method 

(b) Volhard method 

2. Potentiometer (pH Meter) Method
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3. Conductivity (Salt Meter Method)

For methods 1 and 2, the reaction depends upon precipitation of all the chloride as AgC1, 

and detecting the end point either by a color change or observation of electromotive force 

(meter reading).

Whichever method is used, the preparation and standardization of reagents is very 

important. Most reagents can be purchased premixed and standardized in the 

concentrations needed for these reactions. It is preferred that standardized solutions be 

purchased and used for these tests, when possible. Note and adhere to “use by” or 

expiration dates for these solutions. 

Mohr Method Reagents: 

Silver Nitrate (AgNO3): Because AgNO3 is unstable in the presence of light, it should be kept in 

a dark brown glass container and stored in a cool, dark place. As with all reagents, once a portion 

of the AgNO3 has been transferred to another container, unused quantities must not be returned to 

the master container because of the possibility of adulteration. AgNO3 tends to weaken with time, 

so its normality should be checked against a known saline solution before use. 

A. The AgNO3 will need to be prepared and Standardized. 

1. Preparation

Wear protective clothing and eye wear. Dissolve 16.99 grams of reagent grade 

AgNO3 in distilled water and to make exactly 1 liter of solution. This should result 

in a solution that is very slightly stronger than 0.1 Normal. Any 

opalescence in the final solution is due to traces of a chloride or to unclean 

glassware. 

2. Standardization 

Measure out exactly 5.845 grams of reagent grade NaC1. Add enough distilled 

water to make exactly 1000 ml of solution in a volumetric flask. This will produce 

a salt solution of exactly 0.1 Normality. 

Take a measured amount of the salt solution (25 to 40 ml), add potassium 

chromate indicator, and titrate to the end point. 

The addition of calcium carbonate is not strictly necessary, but may make the end 

point easier to see. For those not familiar with the proper end point, a 

representative example can be helpful. Prepare by placing 40-50 ml of distilled 

water in a flask. Add 2 ml of potassium chromate indicator and 0.5 grams calcium 

carbonate. To this solution, add 1 drop of 0.1 N AgNO3 solution. A slight yelloworange color should develop, representing the proper silver-chromate end point.

Calculate normality of the AgNO3 solution by the formula V1N1 = V2N2
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V1 = Volume of NaCl solution

N1 = Normality of NaCl solution

V2 = Volume of AgNO3 solution used

N2 = Normality of AgNO3 solution 

Example:

35.0 ml standard (exactly 0.1 N) NaC1 solution requires 34.2 ml AgNO3 solution 

to reach the end point. Using the formula above: 

 (35.0) (0.10) = 34.2 x 

 3.50 = 34.2 x 

0.1023 = x 

The normality of the AgNO3 reagent is 0.1023. 

To convert to equivalent 0.1 strength AgNO3, (exactly 0.1 N), multiply the actual 

titer by this factor; in the above example, the factor is 1.023. 

Example: 

40.21 ml 0.1023 N AgNO3 is used in the titration

(40.21) (1.023) = 41.13 ml equivalent 0.1 AgNO3. 

Calcium Carbonate: (CaCO3) Should be finely ground, reagent grade.

Potassium Chromate Indicator (K2CrO4): Dissolve 5 grams of K2CrO4 in a volumetric flask 

with distilled water, and make up to 100 m1. 

Volhard Method Reagents:

Silver Nitrate (AgNO3): (see previous pages for preparation and standardization). 

Ammonium Thiocyanate (NH4CNS): This reagent forms a pale reddish-brown color in the 

presence of ferric alum indicator when a slight excess is added to a standard AgNO3 solution 

acidified with nitric acid. 

A. The NH4CNS solution will need to be prepared and standardized prior to use. 

3. Preparation

Dissolve 7.6 grams of reagent grade Ammonium Thiocyanate in about 500 ml

distilled water. Transfer to 1000 ml flask and make up to 1000 ml. 
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4. Standardization 

To a 250 ml flask, add 40 ml 0.1 AgNO3, 5 ml HNO3 (1 + 1), and 2 ml ferric alum 

indicator. Titrate with the NH4CNS solution (about 40 ml) to pale rose or tinge of 

brown end point. Calculate the normality of the thiocyanate solution by the 

formula V1N1 = V2N2 as in the example under AgNO3. The exact normality of the 

AgNO3 solution must be known. 

Ammonium Thiocyanate (NH4CNS): 0.10N – Adjust and standardize by titrating against 0.1 

AgNO3. 

Nitric Acid (HNO3) (1 + 1): Prepare by combining equal volumes of concentrated HNO3 and 

distilled water. As with all acids, add the acid to the water, not the water to the acid. For safety, 

add the acid slowly. 

Nitric Acid (HNO3) (2 percent): Prepare by combining concentrated HNO3 and distilled water in 

the ratio of 3 ml HNO3 per 197 ml water.

Ferric Ammonium Sulfate (Ferric Indicator): Saturated solution of FeNH4 (SO4)2 ∙ 12 H2O 

(held in solution, ratio 1 FeNH4 (SO4)2 to 12 H2O)

Filter Aid: Celite or diatomaceous earth. 

Visual Indicator Methods 

Two visual indicator methods are available for determination of salt in foods. 

Mohr Method 

A. This determination is generally simpler and faster than the Volhard method. It’s the 

official AOAC method for determining the salt content of most foods. It is particularly 

suited for products that are not highly colored which will not interfere with the visual end 

point. 

1. Equipment and Reagents: 

Standard titration burette with stand 

Erlenmeyer flask 

Pipette, if results are to be expressed as grams per 100 ml

Analytical Balance, if results are to be expressed as percent by weight 

Distilled Water

Silver Nitrate (AgNO3), reagent grade of appropriate normality 
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(generally 0.1) 

Calcium Carbonate (CaCO3) for acid products 

Potassium Chromate (K2CrO4) indicator 

2. Procedure 

a. Fill a clean burette with 0.1 N AgNO3. 

b. Put the prescribed amount of sample into the Erlenmeyer flask. 

c. Dilute with about 25 ml distilled water to increase the volume of solution in 

the flask and allow for better agitation and easier end point detection. 

d. Neutralize any naturally occurring acidity (such as in pickles and 

sauerkraut) by adding about 0.5 gram of powdered calcium carbonate 

(CaCO3). This does not need to be weighed but can be estimated by using 

the tip of a spatula. 

e. Add approximately 2 ml (4 to 5 drops) of Potassium Chromate indicator 

(K2CrO4). 

f. Titrate with AgNO3 to the characteristic yellow-orange end point of the 

chromate indicator. 

3. Calculations

Determine, to the nearest one-tenth ml, the amount of AgNO3 necessary to reach 

the end point. Calculate the salt content according to this formula:

S = (T) (N) (0.05845) (100) 

V 

S = Salt Content 

T = ml AgNO3 required to reach the end point 

N = Normality of the AgNO3

V = Sample size - either in ml or grams, depending upon the terms in 

which the results are expressed.

0.05845 = the factor necessary to convert the titration to NaC1 and represents 

the number of grams of NaC1 which will completely react with one 

ml of Normal AgNO3. 
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100 = the factor necessary to convert the results into percent by weight or 

volume. 

Example: 10 ml of pickle juice requires 41.7 ml of exactly 0.1 N AgNO3 to reach 

the proper end point. The percent salt is calculated as follows: 

S = (41.7) (0.10) (0.05845) (100) = 2.44 

10 

Therefore, the salt content is 2.44 grams per 100 ml pickle juice.

If the size of sample and the normality of AgNO3 remain constant, a handy 

mathematical shortcut may be used when many samples are to be tested. Precalculate the following portion of the formula: 

(N) (0.05845) (100) 

 V 

Example: you have several samples of pickle juice to titrate for salt. You know 

from past experience that 0.1 N AgNO3 used in conjunction with a sample size of 

10 ml pickle juice provides a convenient working range with a 100 ml burette. 

You establish a constant as follows: 

N = 0.1 

V = 10 ml

(0.1) (0.05845) (100) = 0.05845 = constant 

10 

The constant factor is then multiplied by the amount of AgNO3 used during each 

titration to obtain the amount of salt in each sample. Say the first sample required 

28.1 ml 0.1 N AgNO3. The calculation is (28.1) (0.05845), or 1.65 grams per 100 

ml of product. All subsequent samples would be calculated in the same manner, 

substituting the actual amount of AgNO3 used to titrate each sample. 

Volhard Method 

A. This method is more complicated and time consuming than the Mohr method. However,

the end point is easier to discern, especially in intensely-colored products. 

1. Equipment and Reagents 

 

Filter paper, Buchner funnel and vacuum source 

Erlenmeyer flask
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250 ml beaker 

Silver Nitrate (AgNO3) 

Nitric Acid HNO3 (1 + 1)

Dilute Nitric Acid (HNO3) (2%)

Filtering aid, such as Celite or diatomaceous earth

Ferric Ammonium Sulfate indicator (FeNH4 (SO4)2 ∙ 12 H2O) 

Ammonium Thiocyanate (NH4CNS) of same normality as AgNO3 used, 

preferably 0.1 N 

2. Procedure 

a. Measure sample and place in Erlenmeyer flask

b. Add 5 ml HNO3 (1 + 1) 

c. Add 50 ml distilled water and about 1/2 gram of filtering aid

d. Add an excess of 0.1 N AgNO3 (usually 30-40 ml) 

e. Stopper flask and shake vigorously 

f. Allow to stand for a few minutes 

g. Filter through rapid filter paper in Buchner funnel. Wash with dilute HNO3

(2 %) and place filtrate in beaker

h. Add 5 ml Ferric Alum indicator

i Titrate filtrate to a permanent, faint brownish tinge using standard 0.1 N 

NH4CNS.

3. Calculations

Subtract the amount of 0.1 N NH4CNS used in step i above from the amount of 0.1 

N AgNO3 used in step d above. The remainder represents "T" in the mathematical 

formula described in the Mohr method. Use the same formula to calculate salt for 

the Volhard method of titration. 
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S = (T) (N) (0.05845) (100) 

V 

Example

To a 10.0 gram sample of product, 40.0 ml 0.1 AgNO3 is added. 

The filtrate requires 10.2 ml 0.1 N NH4CNS to reach the end point. 

0.1 N AgNO3 in reaction = 40.0 - 10.2 = 29.8 = T

S = (29.8) (0.10) (0.05845) (100) 

 10 

S = 1.74 Percent 

Potentiometer (pH meter) Method 

This method is superior to visual titration methods for products with characteristics that interfere 

with visually detecting the correct end point. For example, the intense red color of tomato 

products is likely to mask the yellow-orange end point of the potassium chromate. 

A pH meter is primarily designed for measuring acidity or alkalinity, but it can be easily modified 

to determine salt content by using different types of electrodes. There are many makes and 

models in use. They may vary in the location of electrodes and controls, but the operating 

principle is the same. Consult the instrument’s manual for specific operating instructions. 

Equipment 

Magnetic Stirrer

pH meter with scale divisions of 10 millivolts or less. Range not less than – 700 to + 700 MV. A 

direct-reading model is preferable.

Electrodes: Beckman Silver Billet Combination Electrode (Beckman Instruments Part No. 39187 

or equivalent). Separate electrodes (Silver indicator electrode and Calomel reference electrode) 

for above meter are also satisfactory. The Combination Electrode is used without a silver 

chloride coating. Before using, clean electrode tip with scouring powder and rinse thoroughly 

with water to assure absence of a halide coating.

Electrode Attachment

If using two electrodes, connect the calomel electrode to the proper terminal on the meter using a 

jack adapter. Only one terminal will accept the jack adapter. Connect the silver electrode to the 

other terminal on the meter. 
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Reagents 

1. Sodium chloride standard solution, 0.0856 N. 

2. Silver nitrate standard solution, approximately 0.0856 N. 

Standardization 

Pipette 25 ml aliquot of NaCl solution into a 250 ml beaker and dilute to approximately 100 ml 

with distilled water. Add 5.0 ml HNO3 (1 + 4). Insert electrodes, start magnetic stirrer and 

continue stirring vigorously throughout the titration. Titrate with AgNO3 standard, adding 

increments small enough that the voltage end point and corresponding ml AgNO3 added can be 

determined accurately from a plot of MV readings versus ml AgNO3. Use a total of 50.0 ml 

AgNO3 to obtain complete titration curve.

The end point is the inflection point of curve. Determine by drawing two straight lines with a 45° 

slope to the axes, and tangent to titration curve at the two points of greatest curvature. The 

inflection point is at the intersection with titration curve with a line drawn parallel to and midway 

between the other two lines (see below). From the volume of AgNO3 used, calculate normality 

and adjust to 0.0856 N. Re-standardize occasionally. 

NaCl Potentiometric Titration Curve

Beckman Zeromatic pH Meter
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Preparation of Sample 

Either the solid portion or both the solid and liquid portions should be comminuted with a highspeed blender. If necessary, for the proper operation of the blender, add an equal weight of 

distilled water. Add 1 ml approximately 0.1 N AgNO3 and 5 ml HNO3 (1 + 4) to 100 ml water. 

This should produce not more than a slight turbidity. 

Determination

The voltage end point obtained on pure NaCl solution may be used as specified in this method. 

When extreme accuracy is required, the titration curve must be determined for each sample. 

Using NaCl standard as before, recheck endpoint potential occasionally, and redetermine when 

either the individual electrode, combination electrode, or pH meter is replaced. 

The surfaces of the electrode must be thoroughly rinsed with distilled water and wiped dry after 

each determination.

Samples containing <5.0% sodium chloride: 

Weigh 5.00 ± 0.01 gram of prepared sample (10.00 ± 0.01 gram if equal weight of water is added 

in Step E. Preparation of Sample) in a 250 ml beaker. Dilute to approximately 100 ml with 

distilled water and add 5.00 ml HNO3 (1 + 4). Stir to suspend all insoluble material and allow to 

stand at least 10 minutes for complete solution of chlorides. While stirring, titrate to endpoint 

established in “Standardization.” If salt content is ≤1%, use a 10 ml burette to titrate. 

Percent NaCl = ml 0.0856 N AgNO3 

 10 

Samples containing > 5.0% sodium chloride: 

Weigh 5.00 ± 0.01 gram of prepared sample (10.00 ± 0.01 gram if equal weight of water is added 

in Step E. Preparation of Sample). Transfer to a 100 ml volumetric flask and dilute to volume with 

distilled water. Mix and let stand at least 10 minutes. Mix the sample, allow settling, and transfer 

the aliquot containing 50-250 mg. NaCl to a 250 ml beaker. Dilute to approximately 100 ml with 

distilled water and add 5.00 ml HNO3 (1 + 4). Stir to suspend all insoluble material and allow the 

sample to stand at least 10 minutes for complete solution of chlorides. While stirring, titrate to 

endpoint established in “Standardization.” 

F = dilution factor =100/ml aliquot titrated

Percent NaCl = F x ml 0.0856 N AgNO3 

 10 

Conductivity (salt meter) Method

Another method of determining salt content is by use of a dedicated salt meter. A dedicated salt 

meter is an analytical device that can make a direct reading of the salt content of a product. Only 

instruments which have been approved by the Division shall be used. 
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The current instruments approved are the DiCromat II or DiCromat IIA manufactured by: 

Noramar Co.

P.O. Box 771 

Chagrin Falls, OH 44022 

Phone: 440-338-5740 

FAX: 440-247-3879 

Web site: http://www.noramar.com

When using a salt meter, follow the manufacturer’s instructions for instrument care, calibration, 

use, and sample preparation. Some products may require that the sample be diluted. Follow 

manufacturer’s instructions for dilution of product prior to placing the sample into the salt meter. 

The salt meter should be calibrated for each product that will be routinely tested for salt content. 

A titration method suitable for the product that will be tested should be used to calibrate the salt 

meter. This shall be done on one sample per lot being graded, or daily if more than one lot is 

graded.

The first sample for analysis shall have the salt content determined by one of the titration 

methods. Once the salt content of the first sample has been determined, this product sample will 

be used to calibrate the salt meter in order to use the salt meter for the remaining samples from the 

lot, or lots graded daily. 
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REFERENCE LINKS Version Date

 (Printed for distribution)

7 CFR 43.101, 102, 103, 104, 105, and 106: __________ 

https://www.ecfr.gov/cgi-bin/ECFR?page=browse. 

21 CFR 101.30, 102.33, 130.12: __________ 

https://www.ecfr.gov/cgi-bin/ECFR?page=browse. 

Certification Manual: __________ 

https://www.ams.usda.gov/publications/content/aim-certification-manual.

FDA AMS MOU 225-96-2001: __________ 

http://www.fda.gov/AboutFDA/PartnershipsCollaborations/MemorandaofUnderstandingMOUs/D

omesticMOUs/default.htm. 

FDA Macroanalytical Procedures Manual: __________ 

https://www.fda.gov/food/laboratory-methods-food/macroanalytical-procedures-manual-mpm.

Form SC-637, Laboratory Sample Submittal Sheet: __________ 

https://usdagcc.sharepoint.com/sites/ams/AMSFormsCatalog/Forms/AllItems.aspx. 

General Market Manual: __________ 

https://www.ams.usda.gov/sites/default/files/media/GeneralMarketManual.pdf

General Procedures Manual: __________ 

https://www.ams.usda.gov/publications/content/aim-general-procedures-manual.

Sampling Manual: __________ 

https://www.ams.usda.gov/sites/default/files/media/SamplingManual.pdf.

Sanitation and Safety Manual: __________ 

https://www.ams.usda.gov/publications/content/aim-inspection-series-sanitation-manual.

Section 403 of the Federal Food, Drug and Cosmetic Act (21 U.S.C. 343): __________ 

https://www.ecfr.gov/cgi-bin/ECFR?page=browse

Checked Materials have been printed from the links in this Manual and included for reference.
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APPENDIX I-Thermometer Checks Log

Electronic version of Appendix I-Thermometer Checks Log

ID # _______________________ DATE LAST SERVICE________________

READINGS USDA

°C/°F INITIALS

THERMOMETER

NUMBER

THERMOMETER CHECKS

DATE COMMENTS AND ADJUSTMENTS
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APPENDIX II - Weekly Gram Scale Checks Log

Electronic version of Appendix II - Weekly Gram Scale Checks Log

ID # _______________________ DATE LAST SERVICE_____________

USDA

0 GRAMS 10 GRAMS 100 GRAMS INITIALS

VALUE READING WITH WEIGHT

WEEKLY GRAM SCALE CHECKS

Record to nearest 0.1 GRAM

DATE COMMENTS AND 

ADJUSTMENTS
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APPENDIX III - Weekly Ounce Scale Checks Log

Electronic version of Appendix III - Weekly Ounce Scale Checks Log

OUNCES OUNCES OUNCES INITIALS

ID # _______________________ DATE LAST SERVICE_______________

USDA

0 10 80 

VALUE READING WITH WEIGHT

WEEKLY OUNCE SCALE CHECKS

Record to nearest 0.1 ounce

DATE COMMENTS AND ADJUSTMENTS
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APPENDIX IV - Refractometer Checks Log

Electronic version of Appendix IV - Refractometer Checks Log

COMMENTS AND ADJUSTMENTS

_____degree PRISM USED

DATE

TEMP ** 

OF 

WATER

USDA INITIAL

DEGREES/REF INDEX FOUND

CALIBRATION 

FLUID ***

WATER 

**

PRISM nD 

*

WEEKLY *

DAILY **

RECORD BRIX OR ***

REF INDEX OF FLUID

ID # _______________________ DATE LAST SERVICE__________________

REFRACTOMETER CHECKS
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APPENDIX V - Daily pH Meter Checks Log

Electronic version of Appendix V - Daily pH Meter Checks Log

CRYSTALS?

ID # _______________________ DATE LAST SERVICE________________

ELECTRODES pH 7 pH 10 

FREE OF pH 4 pH 7

COMMENTS AND 

ADJUSTMENTS SLOPE

DAILY pH METER CHECKS

USDA 

INITIALS DATE TIME
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APPENDIX VI - Analytical Glassware Checks Log

Electronic version of Appendix VI - Analytical Glassware Checks Log

EXAMPLE
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APPENDIX VII - Hydrometer Checks Log

Electronic version of Appendix VII - Hydrometer Checks Log

DATE

Non-Certified

READINGS

° BRIX

Certified

USDA 

INITIAL SERIAL NUMBER COMMENTS AND ADJUSTMENTS

ID # ________________________ DATE LAST SERVICED_______________________

HYDROMETER CHECKS
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APPENDIX VIII - Salometer Checks Log

Electronic version of Appendix VIII - Salometer Checks Log

Type I Brine for Pea Maturity (percent NaCl by weight)

Type II Canned Ripe Olives (percent saturation, degrees salometer)

Serial Number or ID___________________ Date Placed in Service_____________________

a. Distilled water b. Reference standard

c. 13 % brine solution Salometer serial #

d. Olive brine __________________

e. Other (State type) Final reading reference

__________________ standard salometer

Meets/Fails reading salometer)

SALOMETER CHECKS

USDA 

Initials

Visual 

inspection for 

damage 

Uncorr 

salometer 

Final 

reading 

(grading 

Verification method indicate a, b, c, d, or e

Date Temp  ̊F Temp 

correction
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X

Z

Y

Z

X

Y

Z

X

Z

Y

Y

Z

X

Y

X

Y

Z

Y

Z

X

Y

Z

X

X

Y

Z

X

APPENDIX IX - Colorimeter Calibration Checks Log - Hunter D45

Electronic version of Appendix IX - Colorimeter Calibration Checks Log - Hunter D45

ID # _______________________ DATE LAST SERVICE__________________

USDA

INITIALS

SCALES COMMENTS AND ADJUSTMENTS

COLORIMETER CALIBRATION CHECKS

HUNTER D45 

DATE (+) OR (-)

READINGS
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APPENDIX X - Colorimeter Calibration Checks Log - Hunter D45D5

Electronic version of Appendix X - Colorimeter Calibration Checks Log - Hunter D45D5

X

Z

Y

Z

X

Y

Z

X

Z

Y

Y

Z

X

Y

X

Y

Z

Y

Z

X

Y

Z

X

X

Y

Z

X

ID # _______________________ DATE LAST SERVICE__________________

USDA

INITIALS

SCALES COMMENTS AND ADJUSTMENTS

COLORIMETER CALIBRATION CHECKS

HUNTER D45D2 

DATE (+) OR (-)

READINGS
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INITIALS

APPENDIX XI - Colorimeter Calibration Checks Log - Macbeth Color-Eye 3000, 3100, and i5 

Electronic version of Appendix XI - Colorimeter Calibration Checks Log - Macbeth Color-Eye 

3000, 3100, and i5

ID # _______________________ DATE LAST SERVICED________________________

CALIBRATED WITH USDA

WHITE TILE? Y, N

COLORIMETER CALIBRATION CHECKS

MACBETH COLOR-EYE 3000, 3100 AND i5

DATE TIME COMMENTS AND ADJUSTMENTS
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APPENDIX XII - Example: Optional Worksheet for Fruit/Sugar Ratio. 

Electronic version of Optional Worksheet for Fruit/Sugar Ratio