The presence of production strain DNA in the product is tested with strain-specific PCR. According to EFSA, the size of the amplified PCR fragment must not exceed the smallest antimicrobial resistance gene (AMRg) in the strain. In any case, the fragment should not exceed 1 kb. Whole genome sequence of the strain is needed for proper designing of the PCR primers. A limit of detection of at least 10 ng/g or mL of product should be achieved. Production strain DNA is used as a positive control to prove the validity of the assay.
Instead of the final product, samples from an earlier step can be analysed as long as they are equally or more concentrated. This usually alleviates problems related to PCR inhibition. Three independent production batches should be analysed, each one in triplicate, i.e. nine samples in total.
All fermentation products are unique, and a proper DNA isolation method needs to be developed case-by-case.
Over the years, Biosafe Ltd has gained plenty of experience with widely varying products and matrices.
This know-how can shorten markedly the time needed for preliminary testing of DNA isolation method, which suits to a particular product.
Optimising the DNA analysis is among the most challenging in vitro analyses required for product approval in the EU. Biosafe experts are happy to help you with this.
To minimize the time and effort during testing, Biosafe asks you details about the test strain and the sample. All information will be kept strictly confidential. The test strain is destroyed after the project.