A false positive for Enteros and Pseudomonas exposed
31 January 2023
During a recent shelf-life study, we found high counts of Pseudomonas spp and Enterobacteriaceae in a product of one of our clients. The validation also showed that the product was positive for high counts of Pseudomonas spp and Enteros.
Various strains of Pseudomonas bacteria have pathogenic properties, which can cause disease in humans. Confirmed Enteros can also indicate a high risk of pathogens!
Granted, we were on alert, but we also thought it was somewhat peculiar. We are familiar with the product, the process and the producer, and this altogether did not really fit the picture of pathogens. We therefore decided to further study this phenomenon and use the bacteria found for identification to establish what bacteria we were dealing with. We found out that it was a perfectly harmless bacteria that occurs naturally in this product. Although the bacteria tested positive on both Entero and Pseudomonas plates, it was not pathogenic to humans.
All was well, and the aimed microbiological shelf life proved realistic. At the same time, we exposed a harmless, non-pathogenic bacteria that gave false positives on not one, but two two culture mediums! Interesting little critter, this one.
Our constant focus on knowing and measuring precisely and asking questions constantly, leads smartfood R&D to most accurately identify microbiological spoilage and food safety risks, in order to provide an answer to the shelf-life issues our clients face.
