A new kinetic model for thermal inactivation of microorganisms: development and validation using Escherichia coli O157:H7 as a test organism.
A new kinetic model has been proposed to simulate the nonlinear behavior of survivor curves frequently observed in thermal inactivation of microorganisms. This model incorporates a time component into the first-order inactivation kinetics and is capable of describing the linear, convex, and concave survivor curves. The model was validated using Escherichia coli O157:H7 as a test microorganism. Ground beef (93% lean) samples inoculated to 10(7) to 10(8) CFU/g of meat were subjected to immersion heating at 55, 57.5, 60, 62.5, and 65 degrees C, respectively, in a water bath. All the survivor curves in this study showed upward concavity. Linear and nonlinear regressions were used to fit the survivor curves to the linear first-order inactivation kinetics and the proposed model. Analyses showed that the new kinetic model provides a much better estimate of the thermal inactivation behavior of E. coli O157:H7 in ground beef.
Huang
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Eastern Regional Research Center, Agricultural Research Service, US Department of Agriculture, Wyndmoor, Pennsylvania 19039-6400, USA. lhuang@arserrc.gov
Juneja
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VK
D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D019453:Escherichia coli O157 / Q000254:growth & development*; D005516:Food Microbiology; D006358:Hot Temperature; D007700:Kinetics; D008461:Meat Products / Q000382:microbiology*; D008954:Models, Biological; D015203:Reproducibility of Results