USDA is an equal opportunity provider, employer, and lender

The contents of this document do not have the force and effect of law and are not meant to bind the public in 

any way. The following is intended only to provide clarity to the public regarding existing requirements 

under the law or agency policies.

National Bioengineered Food Disclosure Standard 

Draft Instructions on Testing Methods

The regulations implementing the National Bioengineered Food Disclosure Standard (Standard) 

identify the standards of performance for detectability testing at 7 CFR 66.9(c). In the final rule, 

AMS indicated it would provide instructions regarding acceptable testing methods to satisfy that 

a food does not contain detectable modified genetic material.

Any regulated entity that is using a food on the AMS List of Bioengineered Foods and does not 

want to include a bioengineered food disclosure because the food or ingredient is highly refined 

and doesnot include detectable modified genetic material, should use the following instructions 

to ensure compliance with 7 CFR 66.9(c).

These instructions address the following:

(1) General considerations in selecting a test method

a. Fit for Purpose

(2) DNA-based methods

(3) Emerging technologies and other methods

(4) General considerations in selecting a laboratory

(5) Recordkeeping requirements

1. General considerations in selecting a test method

When choosing a testing method, regulated entities should ensure the method is fit for purpose. 

Fit for purpose requires the method’s performance to be assessed to determine its suitability to 

provide an answer to a given question or requirement, such as a regulatory requirement or limit, 

in an effective manner. The following factors are critical for ensuring the method is fit for 

purpose:

• Appropriate for the analyte of interest (i.e., define what is being measured);

• Appropriate (validated) for the product/commodity being tested;

• Accuracy, precision, robustness, reliability, and reproducibility of the method;

• Value of the measurement falls within the method’s accurate range (i.e.,appropriate 

Limit of Detection (LOD) and Limit of Quantitation (LOQ) applicable to the 

regulatory requirement); and

• Accessible and practical for testing needs.

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Regulated entities should use validated methods accepted by international bodies (e.g., ISO, 

Codex Alimentarius Commission) and/or validate their own methods to detect the modified 

genetic material. Method validation should consider: sensitivity, specificity, accuracy, 

robustness, probability of detection (POD), limit of detection (LOD), limit of quantification 

(LOQ), applicability, selectivity, species specificity, repeatability, and reproducibility.

Internationally-accepted standards-producing bodies have established criteria that provide a basis 

for developing an analytical scheme to determine the presence and nature of recombinant DNA 

(rDNA) in a food or food ingredient. The International Organization for Standardization’s (ISO) 

International Standard 24276 Foodstuffs -Methods of analysis for detection of genetically 

modified organisms and derived products- General requirements and definitions, specifies how 

to use standards for nucleic acid extraction, and both qualitative and quantitative nucleic acid 

analysis for food matrices. The standards referenced within are: ISO 21571 Nucleic Acid 

Extraction, ISO 21569 Qualitative Nucleic Acid Analysis, and ISO 21570 Quantitative Nucleic 

Acid Analysis. Additionally, guidelines on performance criteria and validation criteria are also 

covered in Codex Alimentarius Commission document CAC/GL 74-2010 Guidelines on 

Performance Criteria and Validation of Methods for Detection, Identification and Quantification 

of Specific DNA Sequences and Specific Proteins in Foods.

2. DNA-based test methods

At this time, polymerase chain reaction (PCR) is the most widely used and commercially 

accepted test method for determining whether modified genetic material is detectable in a food or 

ingredient. PCR can be used to detect known or unknown genetic modifications, single or multigenetic modification events, and qualitative or quantitative results.

Certain DNA sequences are often incorporated into many different products, which enables 

broad-spectrum PCR testing that may be capable of detecting many different events. For some 

matrices, these broad-spectrum tests may be sufficient to detect both known and unknown 

genetic modifications in a food or ingredient. However, such tests may not be capable of 

detecting all events.

In some instances, event-specific or construct-specific tests may be necessary to identify specific 

genetic modifications. When used with appropriate reference materials, PCR testing can detect 

specific single and multi-genetic modification events.

PCR includes both qualitative and quantitative measurements. Qualitative PCR testing will 

verify the presence or absence of modified DNA. Quantitative PCR testing will reveal howmuch 

modified DNA is detectable in a product. While quantitative PCR is preferred, either alternative 

is acceptable.

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While PCR is widely used, it may be limited by PCR-inhibiting compounds and is dependent on 

isolation of high-quality DNA from a sample. In some instances, it may not be fit for purpose to 

test for detectable modified genetic material in a highly processed food product that consists 

almost exclusively of lipids or sugars that can inhibit the PCR reaction.

3. Emerging technologies and other methods

Any DNA-based method that meets the criteria and is fit for purpose for detecting modified 

genetic material may be acceptable. Technology continually progresses and/or advanced 

technology, such as DNA sequencing (e.g., whole genome, target enrichment), may become 

more commercially and economically accessible. As long as these emerging technologies meet 

the requirements of 7 CFR 66.9(c), they would be sufficient to comply with the BE Standard.

4. General consideration in selecting a laboratory

When choosing a testing laboratory, USDA strongly encourages adherence to the ISO 17025 

standard. The laboratory must be able to meet the following standards, as required by the 

regulations at 7 CFR 66.9(c): (1) laboratory quality assurance must ensure the validity and 

reliability of test results; (2) analytical method selection, validation, and verification must ensure 

that the testing method used is appropriate (fit for purpose) and that the laboratory can 

successfully perform the testing, (3) the demonstration of testing validity must ensure consistent 

accurate analytical performance; and (4) method performance specifications must ensure 

analytical tests are sufficiently sensitive for the purposes of the detectability requirements of this 

part.

5. Recordkeeping requirements

Under 7 CFR 66.302(a), regulated entities must maintain customary or reasonable records to 

demonstrate compliance with the Standard. This includes maintaining records in electronic or 

paper format for at least two years beyond the date the food or food product is sold or distributed 

for retail sale. Examples of customary or reasonable records that could be used to demonstrate 

compliance with the disclosure requirements, specifically as it relates to testing to detect 

modified genetic material, include: supply chain records, supplier attestations, third party 

certifications, laboratory testing results, validated process verifications, and other records 

generated or maintained by the regulated entity in the normal course of business. As allowed by 

7 CFR 66.9, regulated entities may also maintain certificates of analysis or other records of 

testing appropriate to the specific food that confirm the absence of modified genetic material.

These records should include details listed above in section 1.

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In the event of an audit or examination under 7 CFR 66.402, AMS intends to look at a regulated 

entity’s ingredient-specific records and does not intend to conduct independent testing of food 

products or ingredients on its own.

References

Gryson, N. (2010). Effect of food processing on plant DNA degradation and PCR-based GMO analysis: 

A review. Anal. Bioanal. Chem.396:2003–2022.

ISO 17025. (2017). General requirements for the complete testing and calibration laboratories.

ISO 24276 (2006). Foodstuffs- Method of analysis for the detection of genetically modified organisms 

and derived products-General requirements and definitions.

ISO 21568 (2005). Foodstuffs- Method of analysis for the detection of genetically modified organisms 

and derived products-Sampling.

ISO 21569 (2005). Foodstuffs- Method of analysis for the detection of genetically modified organisms 

and derived products-Qualitative nucleic acid based methods.

ISO 21570 (2005). Foodstuffs- Method of analysis for the detection of genetically modified organisms 

and derived products-Quantitative nucleic acid based methods.

ISO 21571 (2005). Foodstuffs- Method of analysis for the detection of genetically modified organisms 

and derived products-Nucleic acid extraction.

Terry, C.F., et al. (2002). Detection of genetically modified crops and their derivatives: Critical Steps in 

sample preparation and extraction. J. AOAC Intl. 85:768-774.

Codex Alimentarius Commission. (2009). Guidelines on analytical terminology, CAC/GL 72-2009.

Codex Alimentarius Commission. (2010). Guidelines on performance and validation of methods for 

detection, identification and quantification of specific DNA sequences and specific proteins in foods. 

CAC/GL 74-2010

Bonfini et al. (2002). GMOMETHODS: The European Union database of reference methods for GMO 

analysis. J. of AOAC Int. 95:1713-1719.

Anklam et al. (2002). Validation Studies and Proficiency Testing. J. of AOAC. Int. 85:809-815.

Marmiroli, N. et al. (2008). Methods for detection of GMOs in food and feed. Anal Bioanal Chem. 

392:369-384.

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