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Thermal treatments to control pathogens in muscle foods |
V. K. JUNEJA, Microbial Food Safety Research, USDA-ARS-Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598 The use of heat to inactivate foodborne pathogens is a critical control point and the most common means of assuring the microbiological safety of processed foods. A key to optimization of the heating step is defining the target pathogen’s heat resistance. Quantitative knowledge of the factors in muscle foods that interact and influence the inactivation kinetics are required to accurately estimate how a particular pathogen is likely to behave in a specific food. The effects and interactions of temperature, pH, sodium chloride content, and sodium pyrophosphate concentration are among the variables that were considered when attempting to assess the heat inactivation kinetics of Escherichia coli O157:H7, Listeria monocytogenes, and spores of non-proteolytic Clostridium botulinum. Incorporation of these multiple barriers increased the sensitivity of pathogens to heat, thereby reducing heat requirements and ensuring the safety of ready-to-eat food products. For example, C. botulinum D-values at 75°C in turkey supplemented with 1% salt and 0.1% phosphate at pH 5.5 and 6.25 were 36.1 and 39.1, respectively. When turkey contained 2% salt and 0.2% phosphate, the observed D-values in turkey at pH 5.5 and 6.25 decreased by 42.1% and 22.1%, respectively. Confidence intervals were developed to allow food processors to know the expected heat resistance of these pathogens. The future of thermal death determinations of bacteria will likely rely on predictive thermal inactivation kinetics modeling. Complex multifactorial experiments and analysis to quantify the effects and interactions of additional intrinsic and extrinsic factors and development of “enhanced” predictive models are warranted to ensure the microbiological safety of thermally processed foods.
Session 4, Recent developments in post harvest intervention technologies to control microbial pathogens in muscle foods
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