Effects of media type on Shiga toxigenic E. coli growth patterns

Escherichia coli O157:H7 was declared to be an adulterant in raw ground beef in 1994 by the United States Department of Agriculture Food Safety and Inspection Service following a large and deadly foodborne disease outbreak in the Pacific Northwest involving undercooked hamburgers sold at Jack-in-the-Box restaurants. Due to their recognition as significant human foodborne pathogens, six additional strains (serotypes) of Shiga toxin-producing E. coli (STEC) were also deemed to be adulterants in raw beef products in 2012. The beef processing industry has worked diligently since the mid-1990s to control the presence of E. coli O157:H7 in finished raw products through the implementation of aggressive microbial testing programs and the incorporation of antimicrobial intervention technologies validated to substantially reduce the presence of this pathogenic organism. This effort has occurred within the framework of Hazard Analysis and Critical Control Points (HACCP) programs. With the addition of six additional STEC strains that also must be controlled through these programs, laboratory-testing methods must be developed and implemented to afford the industry a means to accurately document their control programs. Shiga toxin-producing E. coli cultivation, identification, and quantification methods are currently lacking. Establishing behavior patterns for these STECs will allow the beef processing industry to better develop methods for controlling or eliminating them in the food supply. To accomplish this, the prevalence of these organisms must first be established through sampling, but research into which media type is best for enriching samples to recover and identify all STEC organisms has been limited. To determine which media type was best suited for recovery of STECs, we inoculated multiple enrichment media types with the target strains and observed their growth patterns

Electrostatic spray cabinet evaluation to verify uniform delivery of chemical and biological solutions to pre-chilled meat animal carcasses

Shiga toxin-producing Escherichia coli (STEC) are a group of bacteria that cause an estimated 265,000 illnesses, 3,600 hospitalizations, and 30 deaths annually in the United States. STEC are frequently associated with raw or undercooked meat products, prompting the beef industry to develop and apply various antimicrobial intervention technologies during processing operations. The application of chemical antimicrobials to carcasses and fabricated cuts using an electrostatic spray (ESS) system (Figure 1) offers several potential advantages for controlling disease-causing pathogens, including enhanced chemical deposition (coverage) profiles, reduced overspray wastage of foodgrade antimicrobials, and reduced water requirements. The objectives of this study were to (1) calibrate an ESS carcass cabinet installed at the Kansas State University Biosecurity Research Institute, (2) test the chemical deposition profile of the ESS cabinet onto a meat carcass using fluorescent dye, and (3) determine if the ESS could be used to uniformly apply a biological inoculum to a carcass to support pathogen-inoculated validation studies of different chemical intervention technologies to support the needs of the beef processing industry