Agricultural Marketing Service

Commodity Procurement Program

P.O. Box 419205, Mailstop 8718

Kansas City, MO 64141-6205

USDA

COMMODITY REQUIREMENTS DOCUMENT 

(CRD)

DNAC5

NATURAL AMERICAN CHEESE 

FOR USE IN DOMESTIC PROGRAMS

Effective Date: 09/26/2018

USDA is an equal opportunity provider and employer.
USDA COMMODITY REQUIREMENTS DOCUMENT DNAC4

NATURAL AMERICAN CHEESE 

FOR USE IN DOMESTIC PROGRAMS

Table of Contents

Part 1 COMMODITY SPECIFICATIONS................................................................................................1

Section 1.1 COMMODITIES ................................................................................................................1

B. Regulatory Requirements...................................................................................................................1

Section 1.3 QUALITY ASSURANCE...................................................................................................7

Section 1.4 WEIGHT REQUIREMENTS................................................................................................8

Part 2 CONTAINER AND PACKAGING REQUIREMENTS.................................................................8

Section 2.1 GENERAL...........................................................................................................................8

Section 2.2 COMMERCIAL PACKGING REQUIREMENTS.........................................................8

Section 2.3 CONTAINERS AND MATERIALS .................................................................................9

Section 2.4 UNITIZATION REQUIREMENT..................................................................................10

Section 2.5 MONTH/YEAR OF PACK..............................................................................................10

Section 2.6 LOT CODE/CERTIFICATE NUMBER ........................................................................10
DNAC5 Page 1 of 10

Part 1 COMMODITY SPECIFICATIONS

Section 1.1 COMMODITIES

A. Quality of Product

Except as otherwise required, the natural American cheese shall comply with the 

appropriate definition and standard of identify, and all regulations issued pursuant 

to the Federal Food, Drug, and Cosmetic Act, relevant to cheese (21 Code of 

Federal Regulations (CFR) Parts 1-199, including Parts 133.113 for Cheddar 

cheese, Part 133.118 for Colby cheese, Part 133.144 for Granular cheese, and Part

133.146 for grated cheese), as appropriate, for the type of natural American 

cheese specified in the solicitation.

B. Regulatory Requirements

(1) The cheese shall comply with all applicable Federal regulations 

including those contained in 21 CFR § 133.113 for cheddar cheese, 21 

CFR § 101.56 for food nutrient content claims for light or lite, 21 CFR

§101.13 for general principles for nutrient content claims, and 21 CFR §

130.10 Requirements for foods named by use of a nutrient content claim 

and a standardized term. The shredded cheese shall also comply with 21 

CFR § 133.146 for grated chesses.

(2) The cheese shall be prepared and packaged in accordance with good 

manufacturing practices (21 CFR Part 110).

(3) The cheese shall comply with all applicable Federal regulations 

including those contained in 21 CFR § 133.113 for cheddar cheese, 21 

CFR § 101.56 for food nutrient content claims for light or lite, 21 CFR

§101.13 for general principles for nutrient content claims, and 21 CFR §

130.10 Requirements for foods named by use of a nutrient content claim 

and a standardized term. The shredded cheese shall also comply with 21 

CFR § 133.146 for grated chesses.

(4) The delivered cheese shall comply with all applicable Federal and State

mandatory requirements and regulations relating to the preparation, 

packaging, labeling, storage, distribution, and sale of the cheese within 

the commercial marketplace. The delivered cheese shall comply with all 

applicable provisions of the Federal Food, Drug, and Cosmetic Act, the 

Fair Packaging and Labeling Act, and regulations promulgated there 

under. The cheese shall comply with the allergen labeling requirements 

of the Federal Food, Drug, and Cosmetic Act. When the cheese is used 

for the National School Lunch Program, the cheese must comply with all 

applicable provisions of the Child Nutrition Programs.

C. Production Requirements

(1) The cheese delivered to the Government shall have been manufactured 

from pasteurized milk that was produced in the United States and not 

previously owned by the Government, and in plants that were inspected 

and approved by the Dairy Grading Branch, Dairy Programs, Agricultural
DNAC5 Page 2 of 10

Marketing Service (AMS). The USDA AMS plant approval code must 

match the appropriate product or operation code for the commodity being 

offered.

(2) All dairy ingredients shall be pasteurized at a temperature of not less than 

71.7°C (161°F) for a period of not less than 15 seconds, or for a time and 

at a temperature equivalent thereto in phosphatase destruction.

(3) Dairy ingredients used in the manufacture of cheese shall originate from a 

plant that has been approved by the Dairy Grading Branch (DGB), Dairy 

Programs (DP), Agricultural Marketing Service (AMS), USDA. The 

USDA AMS plant approval code must match the appropriate product or 

operation code for the dairy ingredient being used.

(4) Cheese used for cutting shall be clean, free from impurities, mold, rindrot, 

soft spots, salt spots, pests, and other similar defects.

(5) A mold inhibitor may be applied in accordance with the Federal Food, 

Drug, and Cosmetic Act.

(6) All surfaces of the barrel cheese shall be reasonably smooth and closed to 

inhibit mold growth and penetration. However, if the surface is treated 

with an antimycotic and/or vacuum sealed, definite rough surface will be 

allowed. Each lot shall contain only one type and size container. Barrel 

cheese may contain a reasonable amount of whey on the surface of the 

cheese and the liner. “Reasonable” means droplets but less than flowing 

whey on the cheese or the interior of the liner. Barrel cheese may not have 

visible mold at the time of grading.

(7) Cheese which deviates from the specifications contained herein will be 

rejected or, at the discretion of the contracting officer, accepted at 

discounts to be determined by the Government.

(8) Notwithstanding the other provisions of this section, the presence of any 

extraneous material in the natural American cheese will be the basis for 

rejection.

D. Product Age, Temperature and Grade Requirements

Cheese product age and temperature requirements shall comply with the 

following:

Requirement Description

Product Age No lot may contain cheese having a variation of over 30 days 

in dates of manufacture.

All cheese shall be at least 10 days old when graded except 

Reduced Fat, which shall be at least 20 days old when 

graded.

The cheese shall be aged at 38 ̊ to 42 ̊ F (3.5 ̊ to 5.5 ̊ C) prior 

to inspection. This aging may take place before or after the 

cheese is shredded.
DNAC5 Page 3 of 10

AMS Grading Barrel cheese shall be U.S. Extra Grade.

Cheddar cheese shall be U.S. Grade A or higher.

Contractor 

Grading

Barrel cheese shall be equivalent to U.S. Extra Grade.

Cheddar cheese shall be equivalent to U.S. Grade A or 

higher.

Temperature Immediately after aging & physical analysis is completed, 

cheese shall be placed in a cooler and the product 

temperature reduced to 32 ̊ - 40 ̊ F within a 24-hour period 

and held at such temperature until delivered.

D. Composition Requirements

Cheese composition requirements shall comply with the following:

Composition Cheddar Reduced Fat 

Cheddar

Barrel Cheese Report 

test to 

the 

nearest:

Milk fat %

Not less than 50% 

by weight of the 

solids

Range 19.2% - 22.9%

by total weight

Not less than 50% by 

weight of the solids

0.1%

Moisture % No vat more than 

39%

No vat more than 49% No vat more than 

35%

0.1%

Salt % Not to exceed 2% Not to exceed 2% Not to exceed 2% 0.1%

Sodium

No more than 200 

mg of Sodium per 

28 gram serving

No more than 200 

mg of Sodium per 28 

gram serving

No more than 200 

mg of Sodium per 28 

gram serving

N/A

pH value 1 No vat may have a pH value higher than 5.30, except shredded cheese, 

which shall not have a pH value higher than 5.35

0.01

value

Notes: Shredded cheese allows for 1% less milk fat than the standard of identity for 

cheddar cheese.

Reduced fat cheddar cheese shall contain between 1/4 to 1/3 less milk fat than 

that of traditional cheddar cheese.

E. Physical Analysis

Barrel, cheddar, and reduced fat cheddar cheese physical analysis requirements 

shall comply with the following:

Barrel Cheese U.S. Extra 

Grade

Cheddar, Blocks/Prints, 

Slices U.S. Grade AA

Cheddar, Blocks/Prints, 

Slices U.S. Grade A

Flavor: Cheese shall possess a 

pleasing flavor characteristic of 

the variety and type of cheese

Flavor: Cheese shall be fine 

and highly pleasing. The 

cheese may be lacking in

Flavor: Cheese shall possess 

a pleasing flavor. It may be 

lacking in flavor development

1 If a re-test of the product is required, the quinhydrone method will be used by AMS laboratories.
DNAC5 Page 4 of 10

packaged in barrels. The barrel 

cheese may contain a very slight 

bitter taste and slight acid and 

feed flavor, but shall not possess 

any undesirable flavor or odors 

as listed in the U.S. Standards 

for Grades of Bulk American 

Cheese, which are available at 

http://www.ams.usda.gov/AMSv

1.0/getfile?dDocName=STELD

EV3004215.

flavor development or may 

possess slight characteristic 

cheddar cheese flavor. The 

cheese also may possess a 

very slight feed flavor, but 

shall be free from any 

undesirable flavors and odors.

or may possess slight 

characteristic Cheddar cheese 

flavor. It may possess very 

slight acid, or slight feed, but 

shall not possess any 

undesirable flavors and odors.

Body and Texture: The cheese 

shall be firm and sufficiently 

compact to draw a plug for 

examination. The cheese may be 

slight coarse, mealy, open 

(except for Colby), short, weak, 

and curdy to definite degree, but 

it shall not be corky, crumbly, 

gassy, pasty, pinny, slitty, or 

have sweet holes. Mechanical 

openings are permitted in all 

types of the cheese except 

cheddar.

Body and Texture: A plug 

drawn from the cheese shall be 

firm, appear smooth, compact, 

close and should be slightly 

translucent, but may have a 

few small mechanical 

openings. The cheese may be 

very slight open and definitely 

curdy or may be partially 

broken down if more than 3 

weeks old. Shall be free from 

sweet holes, yeast holes, and 

gas holes of any kind. The 

surface shall be free of mold, 

but may be very slightly 

soiled.

Body and Texture: A plug 

drawn from the cheese shall be 

firm, appear smooth, compact, 

close and should be slightly 

translucent, but may have a 

few mechanical openings, if 

not large and connecting. May 

possess not more than two 

sweet holes per plug, but shall 

be free from other gas holes. 

The cheese may be slight open 

and definitely curdy or 

partially broken down if more 

than 3 weeks old. The surface 

shall be free of mold. The 40 

pound blocks surface may be 

very slightly soiled and 

slightly rough. The

40 pound blocks may be 

slightly lopsided.

Color: The barrel cheese shall 

be uncolored.

Color: The cheese shall have 

a uniform, bright attractive 

appearance; practically free 

from white lines or seams. 

May be colored or uncolored, 

but if colored, it should be a 

medium yellow-orange.

Color: The cheese shall have 

a fairly uniform, bright 

attractive appearance. May 

have slight white lines or 

seams, or be very slightly 

wavy. May be colored or 

uncolored, but if colored, it 

should be a medium yelloworange.
DNAC5 Page 5 of 10

Shredded Cheddar Shredded RDU FAT Cheddar RDU FAT Block/Prints, 

Slices

Flavor: Cheese shall have a mild 

pleasing flavor. It may be 

lacking in flavor development, 

or may possess characteristic 

cheddar cheese flavor. Shredded 

cheddar cheese shall meet the 

flavor requirements of U.S. 

Grade A or better according to 

the U.S. Standards for Grades of 

Cheddar Cheese, which are 

available at

http://www.ams.usda.gov/AMSv

1.0/getfile?dDocName=STELD

EV3004465.

Flavor: Reduced fat cheddar 

cheese shall have a pleasing 

flavor. It may be lacking in 

flavor development or may 

possess slight characteristic 

cheddar cheese flavor. It may 

possess very slight acid, bitter, 

or slight feed, but shall not 

possess any undesirable flavors 

and odors.

Flavor: Reduced fat 

cheddar cheese shall have a 

pleasing flavor. It may be 

lacking in flavor 

development or may possess

slight characteristic cheddar 

cheese flavor. It may 

possess very slight acid, 

bitter, or slight feed, but 

shall not possess any 

undesirable flavors and 

odors.

Body and Texture: Shredded 

cheddar cheese may have the 

following body and texture 

characteristics to a slight degree: 

mealy, weak, or pasty. The 

cheese shall be free from all 

foreign and extraneous materials. 

Shredded cheddar cheese shall 

have a height and width up to 

3/16 inch in either dimension. 

Shredded Cheddar cheese shall 

be free flowing and shall not be 

matted. An approved anticaking 

agent may be added as a 

processing aid. If an anticaking 

agent is used, the amount used 

shall be the minimum required to 

produce the desired effect, but 

shall not exceed 2.0% of the 

weight of the shredded cheddar

cheese.

Body and Texture: Shredded 

cheese shall be free flowing and 

of uniform size and shape. It 

shall not mat, crumble, oil off, or 

contain excessive fines.

Body and Texture: The 

block cheese body and 

texture shall be firm, 

compact, and should be 

slightly translucent and 

shiny. It may have a few 

mechanical openings (1 to 3 

openings per plug) if not 

large and connecting. The 

cheese shall be free from 

gas holes. The body may be 

very slight gummy, slight 

mealy or coarse, and 

definite curdy. The cheese 

surfaces shall be free of 

mold but may be slight 

soiled or rough. The cheese 

blocks may be slightly 

lopsided.

Color and Appearance: 

Shredded cheddar cheese shall 

have a uniform bright color, and 

an attractive sheen. The cheese 

may be colored or uncolored, but 

if colored, it shall be a medium 

yellow-orange. No visible signs 

of mold shall be permitted.

Color: The cheese shall have a 

uniform, bright attractive 

appearance, and may be slightly 

wavy. May be colored, or 

uncolored, but if colored, it shall 

be medium yellow-orange. The 

shredded cheese shall not vary in 

color.

Color: The cheese shall 

have a fairly uniform, bright 

attractive appearance, and 

may be slightly wavy. May 

be colored or uncolored, but 

if colored, it shall be 

medium yellow-orange and 

shall not vary in color.
DNAC5 Page 6 of 10

Fines: Shredded cheddar cheese 

shall contain not more than 6.0% 

fines. For shreds whose height 

and/or width is 1/16 inch or less, 

the fines content shall be 

determined using a Standard 

Test Sieve #14 (1.4 mm). For 

shreds whose height and/or 

width is greater than 1/16 inch, 

the fines content shall be 

determined using Standard Test 

Sieve #8 (2.36 mm).

Note: The manufacturer shall 

provide shred size information. 

This information will determine 

the sieve used to measure the 

fines content. If shred size 

information is not provided, the 

Standard Test Sieve #8 will be 

used.

Fines: Shredded RDU FAT 

Cheddar cheese shall contain not 

more that 6.0% fines. For shreds 

whose height and/or width is 

1/16 inch or less, the fines 

content shall be determined 

using a Standard Test Sieve # 14 

(1.4 mm). For shreds whose 

height and/or width is greater 

than 1/16 inch, the fines content 

shall be determined using a 

Standard Test Sieve # 8 

(2.36mm).

Note: The manufacturer shall 

provide shred size information. 

This information will determine 

the sieve used to measure the 

fines content. If shred size 

information is not provided, the 

Standard Test Sieve # 8 will be 

used.

Meltability: The cheese 

shall have been tested for 

meltability in accordance 

with AMS Methods of 

Laboratory Analysis, DA 

Instruction No. 918-RL, and 

shall be at No. 3 or higher.

Meltability: The cheese shall 

have been tested for meltability 

in accordance with AMS 

Methods of Laboratory Analysis, 

DA Instruction No. 918-RL, and 

shall be at No. 3 or higher.

F. Preparation of sample. A minimum of 100 g (3.5 oz) of cheese must be blended to 

uniformity in a minimum time using a Robot Coupe food processor (AOAC 

method 983.18) or equivalent. This uniform sample may then be used in the 

analyses for fat, moisture, salt, and pH. For the meltablility test using a loaf, either 

manually shred 100g (3.5 oz) through a 6.4 mm (1⁄4 in) shredder or a mechanical 

shredder. No further processing is required for the meltability testing of the 

shredded samples.

G. Manufacturer’s/Distributor’s Product Assurance. The manufacturer/distributor 

shall certify that the cheese provided shall meet the requirement of this CRD, 

conform to their own specifications, standards, and quality assurance practices, 

and be the same cheese offered for sale in the commercial market. The USDA 

reserves the right to require proof of conformance.

H. Liability

The contractor shall be liable for losses due to excessive deterioration, mold 

development, or spoilage, which are discovered within 180 days of the date of
DNAC5 Page 7 of 10

delivery to the Government. The liability for reduced-fat cheddar cheese shall be 

five months from the date of delivery.

Section 1.2 KOSHER ONLY PRODUCTS

“Kosher Only” products shall comply with applicable dietary (kosher) laws as established 

by the “613 Council of Kashruth.” Manufacturing plants shall be certified for compliance 

with the aforementioned requirement by contacting the Board of Jewish Education of 

Greater New York (BJENY) at 646-472-5366. At no cost to the vendor, a rabbinic 

supervisor shall be sent to certify compliance of the manufacturing plant with the dietary 

(kosher) laws. 

Section 1.3 QUALITY ASSURANCE

A. The contractor or AMS shall perform the product testing and quality analysis to 

ensure that the product meets the commodity specifications. The results shall 

be evidenced by a Certificate of Analysis (COA) maintained by the contractor. 

The meltability, percentage of moisture, milkfat, salt, fines and pH value as 

well as the quality, date(s) of manufacture, and weight of the natural American 

cheese shall be evidence by certificates issued by AMS, an independent 

commercial laboratory using AOAC International approved methodology, or 

the contractor’s laboratory that complies with the inspection clause in the 

contract. The contracting officer may require submission of COAs representing 

contract performance.

B. Contractors shall notify the Government immediately of lots that fail to meet 

contract requirements.

C. Manufacturer’s/distributor’s certification. When the contractor performs 

quality assurance, the manufacturer/distributor will certify that the cheese 

distributed meets or exceeds the requirements of this CRD.

D. USDA certification. When AMS performs quality assurance, the USDA, AMS, 

DP, DGB, shall be the certifying program. DGB inspectors shall certify the 

quality and acceptability of the cheese in accordance with DGB procedures 

which include selecting random samples of the cheese, evaluating the samples 

for conformance with the salient characteristics of this CRD and other 

contractual requirements, and documenting the findings on official DGB 

certificates. In addition, when required in the solicitation, contract, or purchase 

order, DGB inspectors will examine the cheese for conformance to the United 

States Standards for Condition for Food Containers in effect on the date of the 

solicitation. To qualify for this option the plant must be listed in Dairy Plants 

Surveyed and Approved for USDA Grading Service. The USDA AMS plant 

approval code must match the appropriate product or operation code for the 

commodity being manufactured.

E. USDA INSPECTION NOTES. USDA certification shall include evaluation of 

the quality and condition of samples of the cheese and compliance with 

requirements in the following areas.

- Natural American Cheese Requirements (Sec 1.1).
DNAC5 Page 8 of 10

- Composition Requirements (Sec. 1.1 D). When USDA testing of cheese is 

specified, DGB inspection personnel shall select samples and submit them to the 

USDA, Science and Technology Programs (S&TP) laboratory for analysis.

- Packaging requirements (Part 2).

Section 1.4 WEIGHT REQUIREMENTS

A. The cheese shall be packaged in approximately ten (10) pound prints/blocks, 40 

pound blocks or other sizes stated in the offer and accepted by the Government. 

Shredded cheese shall be packaged in 6/5 pound pouches, and barrel cheese is 

packaged in a 500 pound drum.

B. For random weight blocks and cuts, contractor shall deliver the number of units 

specified by the Government. For barrel cheese, the actual net weight delivered 

shall not vary more than 2% from the net weight specified by the Government.

C. Block cheese shall weigh not less than 40 pounds net weight but not more than 44 

pounds net weight. Print cheese shall weigh not less than ten (10) pounds net 

weight but not more than 11 pounds net weight. Cheese that varies from the net 

weight requirements shall be rejected or, at the discretion of the contracting 

officer, accepted at discounts to be determined by the Government.

D. Individual shipping containers of shredded cheese packed in 6/5 pound pouches 

shall weigh not less than 29.85 pounds. The total net weight of all exact weight 

shipping containers test weighed by AMS from a lot shall not vary more than onetenth (0.1) of the one percent under the aggregate marked net weight of all 

shipping containers within the lot.

E. For sliced cheese, individual slices shall weight 0.50 oz. or 0.75 oz. as indicated in 

the solicitation.

Part 2 CONTAINER AND PACKAGING REQUIREMENTS

Section 2.1 GENERAL

This part provides the container specifications and packaging materials

requirements used under the contract.

Section 2.2 COMMERCIAL PACKGING REQUIREMENTS

A. Contractors shall supply commercial brand products only and shall certify at the 

time of submission of an offer that the commercial product being delivered has a 

history of successful distribution and use in domestic commercial channels and is 

sold on the commercial market with an established level of consumer acceptance.

B. Container and packaging requirements are those used in the current commercial 

shipping practices and shall comply with:

(1) Unitization requirements in Section 2.4.

(2) At contractor’s option, a statement such as “Not for Retail Sale” may be 

printed on the principal display panel of the food label.

(3) The manufacturer’s lot code/lot identification number shall be shown on 
DNAC5 Page 9 of 10

the commercial bill of lading.

(4) Shipping containers shall be marked to show the maximum safe stacking 

height. It is the responsibility of the contractor in cooperation with the 

shipping container manufacturers to determine the safe stacking height.

(5) For identification upon receipt at delivery warehouses, all commerciallabeled product shipping documents shall specify “FOR USDA FOOD 

DISTRIBUTION PROGRAMS.”

C. A company name or brand name shall be shown on all shipping containers.

Section 2.3 CONTAINERS AND MATERIALS

A. All containers and packaging shall be constructed to meet the 

requirements of the Food and Drug Administration (FDA) for safe 

contact with the packaged product. The contractor shall obtain and 

maintain documentation from the container or packaging material 

manufacturer to verify that the containers and packaging materials 

used in this contract were in compliance with the Government’s 

regulatory requirements for safe contact with food products as 

required below:

1. Regulatory Requirements for Commodities and Packaging

2. The commodity shall conform to the applicable provisions of the "Federal 

Food, Drug, and Cosmetic Act" (21 U.S.C. 301 et. seq.), as amended, and 

the relevant regulations. The contractor shall comply with all applicable 

Federal, State and local laws, executive orders, rules and regulations 

related to its performance under this contract.

3. All containers and packaging materials shall be constructed to meet the 

requirements of the Food and Drug Administration for safe contact with 

the packaged product.

4. In addition, all containers and packaging materials shall be 

constructed to comply with the sum concentration levels of 

lead, cadmium, mercury, and hexavalent chromium addressed 

by the Coalition of Northeast Governors (CONEG) model 

legislation. The sum of the concentration levels of lead, 

cadmium, mercury, and/or hexavalent chromium present in 

any package or packaging component shall not exceed 100 

parts per million. Concentration levels shall be determined 

using American Standard of Testing Materials test methods, 

as revised, or U.S. Environmental Protection Agency test 

methods for evaluating solid waste, S-W 846, as revised.

B. If the contractor purchases packaging and container ingredients from

a foreign country and/or the package and container is manufactured in 

a foreign country, the package and container SHALL NOT display 

country of origin labeling. Phrases including, but not limited to, 

“Made in [Name of Foreign Country.]” or “Product of [Name of 

Foreign Country.]” are strictly prohibited.
DNAC5 Page 10 of 10

Section 2.4 UNITIZATION REQUIREMENT

Shipments shall comply with the following unitization requirements:

A. Unless otherwise specified by the Government, all shipments of packaged 

products shall be unitized (palletized and stretch wrapped).

B. Pallets shall be:

(1) Constructed to facilitate the safe handling and transportation of the 

packaged product, as a unit, without loss or damage.

(2) A Number 2, four-way, reversible flush stringer with no broken runners or 

slats.

(3) Suitable for use in the shipment of food products.

C. Plastic stretch wrap shall be:

(1) Constructed of a plastic film which is to be stretched a minimum of 50 

percent beyond its original length when stretched around the pallet load.

(2) Applied as tightly as possible around all tiers of the palletized shipping 

containers. The shipping containers shall be held firmly in place by the 

stretch wrap.

D. Pallet loads shall be:

(1) Stacked in such a way as to minimize the amount that shipping containers 

overhang the edges of pallets.

(2) Blocked and braced or otherwise loaded into the conveyance in a manner 

that prevents shifting during transit.

Section 2.5 MONTH/YEAR OF PACK

A. The month/year of pack shall be shown on all shipping containers.

B. A date fill code may be applied in addition to, but not in lieu of, the month/year of 

pack.

Section 2.6 LOT CODE/CERTIFICATE NUMBER

A lot code or official inspection certificate number shall be legibly marked on all primary 

shipping materials. Contractors may use any type of lot coding system, provided a 

unique code is used to identify each lot under a contract. When requested contractors 

shall provide to the Government an explanation of the lot coding system utilized.