Title: Control of shiga toxin-producing Escherichia coli (STEC) in raw, fermented, and further processed non-intact beef Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2013
Publication Date: May 28, 2013
Citation: Porto Fett, A.C., Shoyer, B.A., Luchansky, J.B. 2013. Control of shiga toxin-producing Escherichia coli (STEC) in raw, fermented, and further processed non-intact beef. Meeting Abstract. STEC Coordinated Agricultural Project Annual Meeting., Lincoln, Nebraska., May 28-30,2013. Volume 1,Page 1.. Technical Abstract: Illnesses due to Shiga toxin-producing Escherichia coli (STEC) have been linked to undercooked ground beef and on occasion to non-intact beef as well. As such, the USDA Food Safety and Inspection Service (FSIS) now considers strains of serotype O157:H7 and strains from a subset of six non-O157:H7 serotypes of STEC as adulterants in raw ground and non-intact beef. The latter would include raw beef products that are enhanced by cubing, frenching, mechanical tenderization, enzymatic/chemical injection, and related processes to tenderize meat and in so doing to render it non-intact. Although considerable scientific information has been published on the fate of serotype O157:H7 strains of STEC in raw, cooked, and further processed beef, considerably less information has been published on other serotypes/strains of STEC in such products. Therefore, along with the assistance of numerous collaborators from the government, academic, and industry sectors, we conducted several studies to comparatively evaluate the translocation and/or subsequent thermal/acidic inactivation of STEC in enhanced beef steaks, ground beef, jerky, goetta, dry/fermented sausage, and prime rib. The intent of this poster is to generally describe the goals, experimental design, results, and significance/impact of these studies. The basic questions addressed were: i) do non-O157:H7 STEC behave similar to O157:H7 strains under food relevant conditions, and ii) are current interventions for serotype O157:H7 strains equally effective for non-O157:H7 strains in beef? The key features of all of these studies are that we: i) inoculated beef directly with pathogenic STEC, not surrogate strains, ii) used pilot scale commercial food processing equipment, not laboratory scale and/or scientific apparatus, and iii) worked with actual steaks, ground beef patties, links, chubs, and prime rib etc. rather than model meat systems such as 3-gram balls and/or slurries of beef. We used a five-strains rifampicin-resistant (100 microgram per ml) cocktail of O157:H7 (USDA-FSIS 011-82, ATCC 43888, ATCC 43889, ATCC 43890, and USDA-FSIS 45756) or a six-strain kanamycin-resistant (100 microgram per ml) cocktail of non-O157 STEC [JB1-95 (serotype O111:H-), CDC 96-3285 (serotype O45:H2), CDC 90-3128 (serotype O103:H2), CDC 97-3068 (serotype O121:H19), 83-75 (serotype O145:NM), and H30 (serotype O26:H11)]. In brief, the longer the cooking and fermentation times, the higher the internal temperature and the lower the pH of the meat, respectively, along with the greater the reduction in levels of STEC. In general, no discernible differences were observed in translocation following blade tenderization or chemical injection of beef subprimals or prime rib, no discernible differences were observed in thermal resistance between non-O157 and O157:H7 strains following cooking of blade tenderized or chemically-injected steaks, frozen or refrigerated ground beef patties, goetta slices, and/or prime rib. Regardless of the type of beef and depending on the processing parameters tested, we observed reductions of ca. 1.5 to greater than 5.0 log. These data filled key data gaps for determining the relative risk of non-intact to intact products, provided data in support of rulemaking for tenderized products, contributed to updating a non-intact beef risk assessment, used for declaring non-O157 STEC an adulterant, answered key questions on thermal/acid death of non-O157 compared with O157:H7 strains, and/or yielded practical knowledge, effective information, and communication tools to reduce STEC risk from beef.