title: Inactivation of Escherichia coli O157:H7 in moisture-enhanced nonintact beef by pan-broiling or roasting with various cooking appliances set at different temperatures.
abstract: This study evaluated inactivation of Escherichia coli O157:H7 in moisture-enhanced restructured nonintact beef cooked to 65 °C using different cooking appliances set at different temperatures. Batches (2 kg) of coarse-ground beef (approximately 5% fat) were mixed with an 8-strain composite (100 mL) of rifampicin-resistant E. coli O157:H7 (6.4 ± 0.1 log CFU/g) and a solution (100 mL) of sodium chloride plus sodium tripolyphosphate to yield concentrations (wt/wt) of 0.5% and 0.25%, respectively, in the final product. Beef portions of 2.54 cm thickness (15 cm dia) were prepared and were vacuum-packaged and frozen (-20 °C, 42 h). Partially thawed (-2.5 ± 1.0 °C) portions were pan-broiled (Presto electric skillet and Sanyo grill) or roasted (Oster toaster oven and Magic Chef kitchen oven) to 65 °C. The appliances were set at, and preheated before cooking to 149 or 204 °C (electric skillet), 149 or 218 °C (grill), 149 or 232 °C (toaster oven), and 149, 204, or 260 °C (kitchen oven). Temperatures of appliances and beef samples were monitored with thermocouples, and meat samples were analyzed for surviving microbial populations. In general, the higher the appliance temperature setting, the shorter the time needed to reach 65 °C, and the higher the edge and surface temperatures of the meat samples. Temperatures of 204 to 260 °C, regardless of appliance, resulted in greater (P < 0.05) pathogen reductions (3.3 to 5.5 log CFU/g) than those obtained at 149 °C (1.5 to 2.4 log CFU/g). The highest (P < 0.05) reduction (5.5 log CFU/g) was obtained in samples cooked in the kitchen oven set at 260 °C. The results should be useful to the food service industry for selection of effective nonintact beef cooking protocols, and for use in risk assessments for nonintact meat products. Practical Application: Results of this study should be useful for developing cooking recommendations to enhance the safety of nonintact beef products, and for use in risk assessments of such products.
authors.affiliation: Center for Meat Safety & Quality, Food Safety Cluster, Dept. of Animal Sciences, Colorado State Univ., 1171 Campus Delivery, Fort Collins, CO 80523-1171, USA.
authors.forename: Cangliang
authors.initials: C
authors.lastname: Shen
authors.forename: Ifigenia
authors.initials: I
authors.lastname: Geornaras
authors.forename: Keith E
authors.initials: KE
authors.lastname: Belk
authors.forename: Gary C
authors.initials: GC
authors.lastname: Smith
authors.forename: John N
authors.initials: JN
authors.lastname: Sofos
mesh_terms: D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D015169:Colony Count, Microbial; D003296:Cooking / Q000295:instrumentation / Q000379:methods*; D024881:Drug Resistance, Bacterial; D019453:Escherichia coli O157 / Q000187:drug effects / Q000254:growth & development*; D005503:Food Additives / Q000737:chemistry; D005511:Food Handling / Q000379:methods*; D017408:Guidelines as Topic; D006358:Hot Temperature; D008461:Meat Products / Q000032:analysis / Q000382:microbiology*; D050296:Microbial Viability; D011122:Polyphosphates / Q000737:chemistry; D012293:Rifampin / Q000494:pharmacology; D012965:Sodium Chloride / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000032:analysis
chemical_list: D005503:Food Additives; D011122:Polyphosphates; D014867:Water; D012965:Sodium Chloride; C005692:triphosphoric acid; D012293:Rifampin