Effective food pathogen testing

Du-Pont-Bax-pathogen-testing With the world’s population growing by six-digit increments every day, the global food industry is under pressure to meet demand for safe and convenient products.

Developing innovative, sustainable solutions requires collaboration that blends the best in food science knowledge, consumer insights, manufacturing expertise and advanced technology.

The BAX System from DuPont Nutrition & Health is an automated method for quickly and easily identifying foodborne pathogens in raw ingredients, finished products and environmental samples. After a standard enrichment, samples are mixed with the provided lysis reagents. This is then heated and cooled to break open sample cells, and transferred to polymerase chain reaction (PCR) tubes with pre-packaged, tableted reagents. The BAX System instrument uses advanced PCR technology to amplify the bacterial DNA and detect pathogens at low levels (as little as one cell per 25g sample). The system automatically analyses the data to provide clear results that are easy to understand and require no expert interpretation.

The system has been independently validated by AFNOR Certification, the AOAC Research Institute, and other organisations and government entities worldwide.

Detecting E. coli O157:H7 and non-O157 STEC in beef

Due to its ability to cause severe illness at low infectious dose, E. coli O157:H7 has been classified as an adulterant in ground beef for about 20 years. Recently, other Shiga toxin-producing E. coli (STEC) has gained recognition as foodborne pathogens in raw beef and fresh produce. These can cause serious, sometimes fatal illness at very low infectious doses. The additional STEC strains are often difficult to detect in food samples using traditional culture methods, especially where low levels of the target must be isolated from high levels of competing background flora.

The BAX testing method, focuses on a unique segment of each pathogen’s DNA. It can accurately detect and identify each targeted E. coli strain in an enriched sample after just 65 minutes of automated, real-time processing. For STEC detection, a screening assay provides presence/absence results for the Shiga toxin genes (stx encoding genes) and intimin (eae encoding genes) to clear negative samples quickly. Any samples with positive screening results can then be tested with the panel assays to identify which “Top Six” STEC strain is present.

Detection analysis in seafood

Vibrio, commonly found in marine and freshwater environments, can cause foodborne illnesses such as cholera. There are 65 known species of Vibrio, but only three are responsible for causing the majority of human illness and infection, namely cholera, parahaemolyticus, and vulnificus.

The BAX System targets these three Vibrio species to reliably detect contamination of oysters, scallops, tuna and other seafood. Not only can the BAX System be used to detect the presence or absence of Vibrio, but it is also validated as a convenient method for performing MPN testing. Simply process all sample dilutions simultaneously in the BAX System instrument. The yes-or-no results are then used to work out the MPN calculations. Whichever technique you choose, results are available less than 24 hours after sampling.