- PCR testing gives the most useful information and is most cost-effective when the sample to be tested is a single-ingredient product in which the DNA is still largely intact.
- Certain processing methods (involving heat, change in pH, etc.) may degrade the DNA in highly-processed products.
- Examples of highly-processed products in which the DNA may be significantly degraded: lecithin, soy sauce, soy oil, dextrose, corn syrup.
- To know the true GMO level of a highly-processed product, use this rule-of-thumb: test the input(s) from which the product was produced, and then maintain traceability to the end product. Example: In order to know the true GMO level of a lot of soy sauce, the producer first tests the lot of soybeans or soy grits from which the soy sauce is made. The final soy sauce product may be tested as an additional step in this quality system.
- The intention of the Non-GMO Project is to drive testing to the most efficient and critical points in the production chain, namely the consolidation of the lot of the single-ingredient product (e.g., the crop) and the seed from which it was produced.
- Even though the emphasis of the Non-GMO Project is on testing of single-ingredient products early in the production chain, multi-ingredient and/or highly-processed products may (and likely will) be tested anywhere in the production chain by any participant or by the Project’s own surveillance testing program.
- The Standard allows for inputs to be verified as compliant with the Standard based on testing alone at any stage of the production chain if
- PCR testing indicates that the GMO content of the input in question is below the relevant action threshold set by the Standard; and
- Appropriate laboratory controls indicate that the DNA of the input is sufficiently intact to allow valid quantitative analysis by PCR.
Inputs that do not meet this criteria, and are therefore not “testable” in this manner, must be verified by lot-specific traceability back to precursors to the input that are testable.