title: Evaluation of Salmonella thermal inactivation model validity for slow cooking of whole-muscle meat roasts in a pilot-scale oven.
abstract: Sublethal heating can increase subsequent thermal resistance of bacteria, which may compromise the validity of thermal process validations for slow-roasted meats. Therefore, this research evaluated the accuracy of a traditional log-linear inactivation model, developed via prior laboratory-scale isothermal tests, and a novel path-dependent model accounting for sublethal injury, applied to pilot-scale slow cooking of whole-muscle roasts. Irradiated turkey breasts, beef rounds, and pork loins were inoculated with an eight-serovar Salmonella cocktail via vacuum tumble marination in a salt-phosphate marinade. The resulting initial Salmonella population in the geometric center (core) was 7.0, 6.3, and 6.3 log CFU/g for turkey, beef, and pork, respectively. Seven different cooking schedules representing industry practices were evaluated in a pilot-scale, moist-air convection oven. Core temperatures recorded during cooking were used to calculate lethality real-time via the log-linear model. The path-dependent model reduced the bias (mean residual) and root mean square error by 4.24 and 4.60 log CFU/g respectively, in turkey; however, the new model did not reduce the prediction error in beef or pork. Overall, results demonstrated that slow-cooked roasts, processed to a computed lethality at or near that required by the regulatory performance standards, as calculated with a state-dependent model, may be underprocessed.
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1323, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Breslin
authors.affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824-1323, USA.
authors.forename: M I
authors.initials: MI
authors.lastname: Tenorio-Bernal
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1323, USA; Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824-1323, USA. marksbp@msu.edu.
authors.forename: B P
authors.initials: BP
authors.lastname: Marks
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1323, USA; Department of Animal Science, Michigan State University, East Lansing, Michigan 48824-1323, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Booren
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, East Lansing, Michigan 48824-1323, USA.
authors.forename: E T
authors.initials: ET
authors.lastname: Ryser
authors.affiliation: Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, Michigan 48824-1323, USA.
authors.forename: N O
authors.initials: NO
authors.lastname: Hall
mesh_terms: D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D003296:Cooking / Q000295:instrumentation / Q000379:methods*; D006358:Hot Temperature; D006801:Humans; D008460:Meat / Q000032:analysis / Q000382:microbiology*; D008954:Models, Biological; D012475:Salmonella / Q000737:chemistry / Q000254:growth & development*; D013552:Swine; D013997:Time Factors; D014422:Turkeys