Title: Evaluation of a multiplex real-time PCR method for detecting Shiga toxin-producing Escherichia coli in beef and comparison to the FSIS microbiology laboratory guidebook method
Authors: Fratamico PM, Wasilenko JL, Garman B, Demarco D, Varkey S, Jensen M, Rhoden K, Tice G
Journal: J Food Prot
Accepted date: 2013 Sep 23
Interpretive summary: Food-borne pathogenic bacteria known as non-O157 Shiga toxin-producing Escherichia coli (STEC) belonging to six specific types (also known as serogroups), namely serogroups O26, O45, O103, O111, O121, and O145, are responsible for the majority of non-O157 STEC infections in the United States, representing a growing public health concern. STEC O157:H7 was classified as an adulterant in beef in 1994 by the Food Safety and Inspection Service (FSIS), and the additional six STEC serogroups were declared as adulterants in 2011. Cattle and other ruminants are reservoirs for these pathogens, thus food of bovine origin may be a vehicle for infection with STEC. Rapid and sensitive methods for detection of these pathogens in animal reservoirs and in food are needed to determine their prevalence and to ensure that food contaminated with STEC does not reach the consumer. The purpose of this study was to evaluate the performance of polymerase chain reaction-based methods known the BAX System real-time STEC suite and the BAX System real-time PCR assay for E. coli O157:H7 and to compare these methods to the FSIS Microbiology Laboratory Guidebook (MLG) methods for detection of the pathogens in ground beef and beef trim samples. Generally, results of the BAX System assays were similar to those of the MLG methods for detecting non-O157 STEC and O157:H7; however, the BAX assays were more rapid and easier to perform. This study demonstrates the feasibility of deploying the BAX assays for the detection and monitoring for the six non-O157 STEC serogroups and O157:H7 in beef, and they are very useful for food industry for the detection of STEC. The BAX system approach for non-O157 STEC detection could easily be expanded to include additional assays should regulations continue to expand into other serogroups of public health concern.
Related projects: Genomic and Proteomic Analysis of Foodborne Pathogens