r 

F f 

CONSUMER NG SERVICE 

AND VEGETABlE 

PROCESSED PRODUCTS STANDARDIZ-".TION AND INSPECTION BRANCH 
PREFACE 

DETERMINATION OF CONSISTENCY 

September, 1971 

These instructions are designed primarily for Processed 

Fruit and Vegetable Inspectors of the U. S. Department of 

Agriculture. They are not intended to be a comprehensive 

treatise on the subject but give background information 

and guide-lines to assist in the uniform application and 

interpretation of USDA grade standards and other simila~ 

specifications. 

These instructions are revised as necessary without public 

notice and no mailing list is maintained as a public 

advisory of such changes. 

The citation of any data, criteria, techniques, illustrations, 

copyrighted material, or pictorial representation accredited 

to private authorship is used with the permission of the 

individuals or sources cited. Unless a specific accreditation 

is referenced, the information herein has been compiled and/or 

developed from sources available to the public as well as from 

technical knowledge of personnel in the Department. 

Compliance with the suggested guide-lines and other pertinent 

information herein does not excuse any one from failure to 

comply with the Federal Food, Drug, and Cosmetic Act or any 

other applicable Federal or State laws and/or regulations. 

Except for official USDA inspection aids or devices and color 

guides (or standards) produced under license of the Department, 

the mention of any supplier, patented device, product, brandname, or equipment does not imply endorsement by the Department 

over any other similar, or equally effective, material. 

Information contained in this instruction is available to the 

public. Inquiries as to availability of portions of this 

instruction and copying or reproduction privileges should be 

addressed to: 

September, 1971 

Chief 

Processed Products Standardization 

and Inspection Branch 

Fruit and Vegetable Division~ C&MS 

U. S. Department of Agriculture 

Hashington, D@ Co 20250 

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TOMATO 

PRODUCTS 

METHODS 

DETERMINATION OF CONSISTENCY 

September, 1971 

[R E S E R V E D F 0 R F U T U R E D E V E L 0 P M E N T S] 

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TOMATO 

PRODUCTS 

METHODS 

DETERMINATION OF CONSISTENCY 

September, 1971 

DETERMINATION OF CONSISTENCY 

INTRODUCTION AND BACKGROUND 

The consistency of tomato paste and tomato puree can be measured 

and expressed in any number of ways. Considerable efforts are expended to continually improve the consistency of these and other tomato 

products -- to make them thicker or more viscous. The consistency is 

dependent upon many variables, among which are: (1) variety of tomato; (2) type of "break"; (3) particle size; and (4) method of concentrating. 

With the advent of the tomato paste "futures" market, a measurement of the consistency of tomato paste scheduled for delivery against 

exchange contracts must be determined. 

Also, more and more packers and buyers are requesting a "consistency determination" for their tomato paste and puree packs and 

purchases. 

PURPOSE AND SCOPE 

This procedure sets forth a method -- using, basically, the 

Bostwick Consistometer -- to determine the consistency of tomato paste 

and/or tomato puree with a concentration of 12.0% or more of natural 

tomato soluble solids (N.T.S.S.). 

Also, the consistency of tomato puree having a concentration of 

less than 12.0% N.T.S.S. may be determined; the undiluted puree will 

be used in these instances. 

Unless another method is specifically requested, these instructions 

shall provide a uniform procedure to use for determining and reporting 

the consistency of tomato paste or tomato puree. 

This procedure may be superseded by another or alternate method 

which may be requested or specified by an applicant. However, a copy 

of the methodology requested must be furnished by the applicant to 

the inspector. 

FUTURES 

The following method will be used for determination of consistency 

of tomato paste that is offered in delivery of tomato paste "futures" 

contracts. 

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TOivlATO 

PRODUCTS 

METHODS 

DETER!v1INATION OF CONSISTENCY 

September, 1971 

[R E S E R V E D F 0 R F U T U R E D E V E L 0 P M E N T SJ 

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TOMATO 

PRODUCTS 

METHODS 

EQUIPMENT 

DETERMINATION OF CONSISTENCY 

September, 1971 

(1) Bostwick Consistometer - (Cenco - Bostwick Consistometer, 

Central Scientific Company No. 24925). The instrument must have a 

smooth, flat trough, free from buckles or other distortions. There 

must be no more than a slight leakage under the gate when the gate 

is closed and sample is allowed to stand in the reservoir for 

several minutes. Be sure that the gate moves freely and opens completely when tripped. 

(2) Spirit Level Must be of a size to fit into lengthwise 

trough of consistometer. 

(3) Balance - The capacity should be of 800 grams or more with 

accuracy to~ 0.5 grams. 

(4) Abbe' Refractometer - Check adjustment and standardize with 

distilled water before using. Distilled water at 20° C should have a 

refractive index of 1~330. 

(5) Stop Watch - or interval timer. 

(6) Straight Edge - Used to properly level product in reservoir. 

(7) 500 ml. Beaker - For mixing the water with the tomato product. 

(8) Spoon - For stirring. 

GIVEN OR DETERMINED - The N.T.S.S. of the sample. 

PREPARATION OF SAt\1PLE 

(1) Using the nomograph (Inspection Aid No. 93), determine 

proper amounts of product and distilled water to mix to produce a 

12.0 percent concentration. 

(2) Tare a 500 ml. beaker. 

(3) Weigh indicated amount of water into beaker. 

(4) Add 100 grams of product. (Add last portion of product 

against side of beaker above water level. This will permit accurate 

weight adjustment of product before it contacts water.) 

(5) Thoroughly mix by stirring -- taking care to minimize 

incorporating of air into mixture. 

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TO !viA TO 

PRODUCTS 

METHODS 

DETE~~INATION OF CONSISTENCY 

September, 1971 

(R E S E R V E D F 0 R F U T U R E D E V E L 0 P M E N T S] 

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TO.tvlltTO 

PRODUCTS 

Iv1ETHODS 

DETEIDJliNATION OF CONSISTENCY 

September, 1971 

PREPP."RA.TION OF SAJviPLE continuation 

Check sides of beaker and stir an.y product into 

mixture"' 

( Remix and continue s until all lumps of 

are dissolvedo 

Check 

Check 

refractometer,. 

ust to 20° C + 1° C. 

of mu:ed sample on 

Refracti ~ve index of properly 

l 3508 to 1 3511, corrected to 20° Co 

12.0 t Do % N T.S.S. 

diluted sample should read 

These readings convert to 

PROCEDURE 

(1) ust end-to-end level of Bostwick Consistometer means 

of a t level aced in of instrwnent Side-to-side level 

may be adjusted means of the built-in spirit level 

fv1ix sample and pour immediate into reseTvoir 

chamber of consistometer 

( Sl t oveTfill reser·voir::: avoidiilg ir1corpo:ration of 

alr bt.1bb es 

leased 

\.. ) and after 30 sec:onO.s) :measu.:-re :m.&~x.i~1lLUTl 

dlstan_ce flow~ 

Read dls tan.ce nearest 0 l clTL, 
TOMATO 

PRODUCTS DETERMINATION OF CONSISTENCY 

METHODS September, 1971 

[R E S E R V E D F 0 R F U T U R E D E V E L 0 P M E N T S] 

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TOMATO 

PRODUCTS 

METHODS 

PROCEDURE continuation 

DETERMINATION OF CONSISTENCY 

September, 1971 

(8) Thoroughly wash and dry consistometer and repeat procedure 

using a second portion of the same sample. Always remix sample before 

transferring to instrument. 

[Do not wash instrument with hot water if it is to be 

used immediately for the next determination as this 

may result in an increase in temperature of the sample. For highest accuracy, the instrument should be 

maintained at a temperature of 20° C ± 1° C.] 

(9) If the first two readings (of the same sample) vary by more 

than 0.2 em., repeat a third (or possibly more) procedures until 

apparent satisfactory agreement is obtained. 

(10) Calculate and report the average of two or more readings 

for any one single sample, excluding any that appear to be abnormal. 

CERTIFICATION 

The results of the method outlined herein will be declared as 

shown in the following examples: 

In the body of the certificate: 

Consistency (Bostwick-Consistometer Method) 

at 12.0% Nat·:.Iral Tomato Soluble Solids: 

Range ------- 6.1 em. to 7.3 em. 

Average----- 6.7 em. 

For tomato puree which contains less than 12.0% N.T.S.S., and 

on which a consistency determination is made on the undiluted product, 

certify: 

Consistency (Bostwick-Consistometer Method) 

at 10.2% Natural Tomato Soluble Solids: 

Range ------- 9.4 em. to 11.1 em. 

Average ----- 10.2 em. 

Any other requested method of measuring the consistency of tomato 

puree or paste may be certified; provided, that the results of such 

measurements are expressed in the terms used in the specified method 

and a copy of the methodology of the procedure is available upon 

request. 

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TOMATO 

PRODUCTS 

METHODS 

DETERMINATION OF CONSISTENCY 

September, 1971 

[R E S E R V E D F 0 R F U T U R E D E V E L 0 P M E N T S] 

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U.S. DEPARTMENT OF AGRICULTURE 

CONSUMER AND MARKETING SERVICE 

FRUIT AND VEGETABLE DIVISION 

CONCENTRATED TOMATO PRODUCTS 

DILUTION CHART -GRAMS OF WATER TO BE ADDED 

TO 100 GRAMS OF PRODUCT TO OBTAIN 12 PERCENT 

N. T.S.S. FOR CONSISTENCY DETERMINA TlON 

INSPECTION AID NO. 93 

September 1971 

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