title: Thermal Inactivation of Shiga Toxin-Producing Escherichia coli Cells within Cubed Beef Steaks following Cooking on a Griddle.
abstract: Thermal inactivation of Shiga toxin-producing Escherichia coli (STEC) cells within knitted/cubed beef steaks following cooking on a nonstick griddle was quantified. Both faces of each beef cutlet (ca. 64 g; ca. 8.5 cm length by 10.5 cm width by 0.75 cm height) were surface inoculated (ca. 6.6 log CFU/g) with 250 μl of a rifampin-resistant cocktail composed of single strains from each of eight target serogroups of STEC: O26:H11, O45:H2, O103:H2, O104:H4, O111:H(2), O121:H19, O145:NM, and O157:H7. Next, inoculated steaks were (i) passed once through a mechanical tenderizer and then passed one additional time through the tenderizer perpendicular to the orientation of the first pass (single cubed steak; SCS) or (ii) passed once through a mechanical tenderizer, and then two tenderized cutlets were knitted together by passage concomitantly through the tenderizer two additional times perpendicular to the orientation of the previous pass (double cubed steak; DCS). SCS and DCS were individually cooked for up to 3.5 min per side in 30 ml of extra virgin olive oil heated to 191.5°C (376.7°F) on a hard-anodized aluminum nonstick griddle using a flat-surface electric ceramic hot plate. Regardless of steak preparation (i.e., single versus double cubed steaks), as expected, the longer the cooking time, the higher the final internal temperature, and the greater the inactivation of STEC cells within cubed steaks. The average final internal temperatures of SCS cooked for up 2.5 min and DCS cooked for up to 3.5 min ranged from 59.8 to 94.7°C and 40.3 to 82.2°C, respectively. Cooking SCS and DCS on an aluminum griddle set at ca. 191.5°C for 0.5 to 2.5 min and 1.0 to 3.5 min per side, respectively, resulted in total reductions in pathogen levels of ca. 1.0 to ≥6.8 log CFU/g. These data validated that cooking SCS (ca. 0.6 cm thick) or DCS (ca. 1.3 cm thick) on a nonstick aluminum griddle heated at 191.5°C for at least 1.25 and 3.0 min per side, respectively, was sufficient to achieve a 5.0log reduction in the levels of the single strains from each of the eight target STEC serogroups tested.
authors.affiliation: Pennsylvania State University, 201 Old Main, University Park, Pennsylvania 16802, USA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Swartz
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Luchansky
authors.affiliation: Kansas State University, 101 Trotter Hall, Manhattan, Kansas 66506, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Kulas
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
authors.forename: Bradley A
authors.initials: BA
authors.lastname: Shoyer
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Shane
authors.affiliation: Delaware Valley College, 700 East Butler Avenue, Doylestown, Pennsylvania 18901, USA.
authors.forename: Hannah
authors.initials: H
authors.lastname: Strasser
authors.affiliation: Drexel University, 3001 Market Street, Philadelphia, Pennsylvania 19014, USA.
authors.forename: Madison
authors.initials: M
authors.lastname: Munson
authors.affiliation: 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.forename: Anna C S
authors.initials: AC
authors.lastname: Porto-Fett
mesh_terms: D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003296:Cooking / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005511:Food Handling / Q000379:methods; D005516:Food Microbiology; D006358:Hot Temperature; D000069466:Red Meat / Q000382:microbiology*; D054323:Shiga-Toxigenic Escherichia coli / Q000302:isolation & purification*