An official website of the United States government.
Our overall hypothesis is that Salmonella inactivation rate on low-moisture foods is a function of product composition, water activity, the mode of contamination, the time between contamination and pasteurization, and the type of lethal treatment. Understanding these functional relationships will enhance the probability of achieving the overall goal, which is to reduce the risk of salmonellosis associated with low-moisture foods, by developing data, knowledge, and tools that account for critical product and process factors affecting the resistance of Salmonella to processing interventions across multiple low-moisture product types. <P>The specific objectives are: (1) To quantify the relationship between Salmonella inactivation rate and (a) product factors (water activity, fat content, structure), and (b) time between contamination and pasteurization for multiple pasteurization methods and low-moisture product categories, (2) To expand and validate novel inactivation models accounting for the significant product and process factors, via Salmonella-inoculated, pilot-scale challenge studies on representative products subjected to multiple pasteurization methods, and (3) To develop pasteurization scale-up and validation strategies that account for inherent uncertainty in the inactivation models. This project will be the first to quantitatively model the complex relationship between food product composition/structure, time between contamination and pasteurization, and inactivation rate, and then validate the inactivation models via Salmonella-inoculated, pilot-scale challenge studies with multiple products and processing technologies - all aimed at our overall program mission of ensuring reliable validations of pasteurization processes. <P>Specific results will include: (1) sound scientific data and validated models for Salmonella inactivation on/in dry foods, as a function of critical product and process factors, subjected to key pasteurization technologies, and (2) guidelines for reliable application of project results to commercial process validations. <br/>These results will enable researchers and the food industry to: (1) Use validated inactivation models that are broadly applicable for evaluating pasteurization processes for low-moisture foods, and (2) Optimize pasteurization processes with respect to key product and process attributes.
Non-Technical Summary:<br/>
Salmonella contamination of low-moisture foods is an emerging and vexing food safety challenge, reflected in recent nationwide outbreaks/recalls (e.g., nuts, cereal products, and spices). Although Salmonella is known to be extremely resistant to lethal treatments on low-moisture foods, there is an acute lack of data and tools for reliable pasteurization validations for these products. The overall goal is to reduce the risk of salmonellosis associated with low-moisture foods, by accounting for critical product and process factors affecting Salmonella resistance to interventions across multiple product types. <br/>The specific objectives are to: (1) quantify the relationship between Salmonella inactivation rate and (a) product factors (composition and structure), and (b) time between contamination and pasteurization, (2) expand and validate novel inactivation models accounting for the significant intrinsic and extrinsic factors, via Salmonella-inoculated, pilot-scale challenge studies using multiple pasteurization technologies, and (3) develop pasteurization scale-up and validation strategies that account for inherent uncertainty in the inactivation models.
<br/>The overall plan will entail: (1) bench-scale inactivation trials with Salmonella cocktails on three classes of products (large particulates, powders, and pastes), with varying compositions, inoculation methods, and post-contamination storage periods, and using multiple intervention processes (moist-air heat, radio frequency energy, and low-energy X-ray), (2) modification of novel inactivation models, (3) pilot-scale validation trials, and (4) development of recommendations for appropriate application of the lethality models to commercial pasteurization processes. This multi-disciplinary project will generate and validate Salmonella lethality data and tools to fill a critical industry need related to pasteurization of low-moisture foods.
<P>
Approach:<br/>
First, we will compare the dose-dependent effects of acute oral exposure of 8-ketotrichothecenes (3-ADON, 15-ADON, NIV, FX and D3G) on magnitude and duration of anorexia in the mouse as compared to a vehicle control. In parallel, additional groups of mice will be orally dosed with 8-ketotrichothecenes and then blood will be collected at intervals over a 24 h period and analyzed for plasma CCK and PYY. We will assign TEFs to each of the 8-ketotrichothecenes based on their comparative anorectic and gut satiety hormone responses. Second, we will compare the dose-dependent effects of acute oral exposure of DON, 3-ADON, 15-ADON, NIV, FX and D3G on the emetic responses in mink. In parallel, additional groups of mink will be orally dosed with 8-ketotrichothecenes and then blood will be collected at intervals and analyzed for plasma CCK and PYY. We will assign TEFs to each of the 8-ketotrichothecenes based on their comparative emetic and gut satiety hormone responses.Third, in vitro assays will be developed that will indicate the TEQs of food samples. This assay will be based on the capacity of 8-ketrotrichothecenes to induce calcium influx and gut satiety hormone release in enteroendocrine cells. It will have two components. The first will be an immunoaffinity isolation and concentration step for all 8-ketotrichothecenes in the food sample. The second will be a cell-based assay using TAS2R-induced calcium influx and/or satiety peptide release.