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The first objective is to develop and verify methods for characterization, measurement and prediction of engineering and biochemical properties of foods as needed in process design and analysis, and product development. <P>The second objective is to measure and model process dependent kinetic parameters which affect food quality and safety attributes. <P>The third objective is to identify and characterize transport mechanisms occurring in food processes. <P>The last objective is to develop mathematical models for simulation, prediction, design, and improvement of food processes.
Non-Technical Summary: Small meat processors historically have used slow-cooking processes to produce niche-market items such as beef roasts and hams. These slow-cooking processes fall outside establshed USDA cooking guidelines. There is concern that pathogenic bacteria may grow enough during the sublethal-temperature portion of slow-cooking that later cooking will not produce a safe product. In this project we will develop computer-based predictive tools to help small processors evaluate their slow-cooking processes and establish validated critical limits for slow-cooking for roast beef and ham. <P> Approach: Small meat processors historically have used slow-cooking processes to produce niche-market items such as beef roasts and hams. These slow-cooking processes fall outside established USDA cooking guidelines. There is concern that pathogenic Escherichia coli and Salmonella may grow enough during the sublethal-temperature portion of slow-cooking that later cooking will not achieve enough lethality to produce a safe product. There is also concern over whether Staphylococcus aureus will grow enough to produce unsafe levels of heat-stable enterotoxin(s) during the sublethal portion of slow-cooking. In this project we will develop computer-based predictive tools to help small processors evaluate their slow-cooking processes and establish validated critical limits for slow-cooking for roast beef and ham. These tools will account for the time/temperature history during both the sublethal and lethal portions of slow-cooking processes. Initial studies will determine the industry-realistic conditions which result in the greatest thermotolerance for E. coli O157:H7 and Salmonella cells. These conditions will then be used in thermal death challenge studies used to develop the tool. To determine an allowable level of S. aureus growth during slow-cooking, we will conduct a processor survey to determine levels of this pathogen on the surface of beef roasts and hams prior to cooking. We will also survey processors about ingredients added to beef roasts and hams, so that we can develop a representative formulations for inoculation studies. Then we will conduct inoculation studies to determine growth and thermal death kinetics for each of the three pathogens in beef roasts and hams. Finally, we will create the computer-based predictive tools, and validate the tools by comparing predicted results to the results of commercial-scale challenge studies.