The overall objective of this project is to improve our ability to predict and control the behavior of Salmonella in dry foods (i.e., foods with insufficient moisture to allow microbial growth). This project will provide improved predictions of inactivation of Salmonella in low moisture foods that have a history of transmitting salmonellosis. This research will provide a quantitative understanding of the factors that affect the ability of Salmonella to survive in low moisture foods that can be used in the development of risk assessments. In addition the project will increase our understanding of how low moisture foods can be formulated to decrease the probability that Salmonella will survive in the product. The result of the project will be improved safety of low moisture foods
There is a long history of low moisture foods causing foodborne illness through Salmonella contamination, but we have a poor understanding of what factors influence the survival of this pathogen in these foods. The goal of this project is to better understand the role of food components in the survival of Salmonella in low moisture foods. The results of this research will be used by government and industry to improve risk assessments for specific food products. This research will provide a quantitative understanding of the factors that affect the ability of Salmonella to survive in low moisture foods, and an understanding of how these foods can be manipulated to decrease Salmonella survival. Our major hypothesis is that the physical state of water is an important factor influencing survival of Salmonella in low moisture foods, and that food composition will have a significant influence on this property. One objective of this project is to produce valid predictive models based on temperature, water activity, and molecular mobility. Another objective is to determine the influence of water mobility on the activity of hydrophobic antimicrobials against Salmonella in low moisture foods. Research results will be applied to foods known to transmit Salmonella including chocolate, dairy powders, and peanut and cereal products.
To achieve our objective it is necessary to develop an understanding the role of food components in the survival of Salmonella in low moisture foods. We will determine the influence of fat-water interactions on the molecular mobility of water and their influence on the kinetics of Salmonella survival in low moisture foods by formulating cocoa- and peanut-based model systems with lipids of different hydrophobicities. We will inoculate these model systems with Salmonella and determine survival at temperatures ranging from 20 to 80 C over periods of up to 6 months. We will develop predictive models for Salmonella survival in fat-containing low moisture foods based on measures of water mobility, water activity, and fat content. These models will be validated by obtaining Salmonella survival data form low moisture foods including peanut butter, chocolate, powdered milk, and toasted oat cereal. We will also determine the influence of water mobility on the activity of hydrophobic antimicrobials against Salmonella in peanut, chocolate and dry cereals.