title: Fate of Escherichia coli O157:H7 in mechanically tenderized beef prime rib following searing, cooking, and holding under commercial conditions.
abstract: We evaluated the effect of commercial times and temperatures for searing, cooking, and holding on the destruction of Escherichia coli O157:H7 (ECOH) within mechanically tenderized prime rib. Boneless beef ribeye was inoculated on the fat side with ca. 5.7 log CFU/g of a five-strain cocktail of ECOH and then passed once through a mechanical tenderizer with the fat side facing upward. The inoculated and tenderized prime rib was seared by broiling at 260°C for 15 min in a conventional oven and then cooked in a commercial convection oven at 121.1°C to internal temperatures of 37.8, 48.9, 60.0, and 71.1°C before being placed in a commercial holding oven maintained at 60.0°C for up to 8 h. After searing, ECOH levels decreased by ca. 1.0 log CFU/g. Following cooking to internal temperatures of 37.8 to 71.1°C, pathogen levels decreased by an additional ca. 2.7 to 4.0 log CFU/g. After cooking to 37.8, 48.9, or 60.0°C and then warm holding at 60.0°C for 2 h, pathogen levels increased by ca. 0.2 to 0.7 log CFU/g. However, for prime rib cooked to 37.8°C, pathogen levels remained relatively unchanged over the next 6 h of warm holding, whereas for those cooked to 48.9 or 60.0°C pathogen levels decreased by ca. 0.3 to 0.7 log CFU/g over the next 6 h of warm holding. In contrast, after cooking prime rib to 71.1°C and holding for up to 8 h at 60.0°C, ECOH levels decreased by an additional ca. 0.5 log CFU/g. Our results demonstrated that to achieve a 5.0-log reduction of ECOH in blade tenderized prime rib, it would be necessary to sear at 260°C for 15 min, cook prime rib to internal temperatures of 48.9, 60.0, or 71.1°C, and then hold at 60.0°C for at least 8 h.
authors: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA. anna.portofett@ars.usda.gov
authors: Anna C S
authors: AC
authors: Porto-Fett
authors: Bradley A
authors: BA
authors: Shoyer
authors: Harshavardhan
authors: H
authors: Thippareddi
authors: John B
authors: JB
authors: Luchansky
mesh_terms: D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003296:Cooking / Q000379:methods; D019453:Escherichia coli O157 / Q000254:growth & development*; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D008460:Meat / Q000382:microbiology*; D013696:Temperature; D013997:Time Factors