Microbial testing

Microbial testing screens a product for bacteria, yeast and mold, either as total counts or as specific organisms that can cause illness.

Typical panels include total aerobic bacteria, total yeast and mold, and targeted pathogens such as Salmonella, Escherichia coli strains and Aspergillus species. Methods range from culturing samples on growth media to DNA-based detection that identifies an organism by its genetic signature. Contamination can originate in the field, in drying and storage, in processing water or in packaging.

On a certificate of analysis, count results are reported in colony-forming units per gram against an action limit, and pathogen results are reported as present or absent in a stated sample amount. A pass means the sample met the limits for that product type; limits are stricter for products taken by mouth than for topicals. The section is worth reading for products intended for animals as well, since pets can be affected by the same organisms. The test reflects the sample on the test date, not how the product was stored afterward.