Impact of Consumer Efforts to Prevent Cross Contamination during Storage of Refrigerated Foods

Non-Technical Summary: Home refrigerators can harbor pathogenic bacteria that pose a potential to contaminate stored foods. Consumers should be informed about safe handling of refrigerated foods and proper cleaning of home refrigerators to reduce the risk of food contaminations. However, despite numerous studies on consumer refrigeration practices, how storage conditions of refrigerated foods in the home impact consumer health remains to be fully assessed. Using a combination of microbiological studies, and in-home observations and surveys, this project will quantify the risk of mishandling and cross contamination of foods, the dynamics of microbial survival and growth, as well as factors which affect bacterial transfer efficiency during refrigerator storage. In response to the findings, risk communication messages appropriate for consumers will be developed and disseminated to the public in order to minimize the risk of food-borne illnesses associated with improper handling and storage of refrigerated foods in the home. <P> Approach: In-home interviews regarding food refrigeration practices will be conducted. A series of questions will be asked about the respondents handling practices of chilled foods, procedures taken to prevent cross contamination, refrigerator cleaning practices, and demographic data. To evaluate the incidence of food-mediated infections, the participants will also be asked if during the last year they suspected that they or their family members had suffered from a foodborne illness which included self-medication, doctor visiting/medication or hospitalization due to the illness. Refrigerators will be visually assessed by trained interviewers using a refrigerator checklist. The checklist will include the kinds of food in the refrigerator and whether there are any spoiled or moldy foods, or any signs of cross contamination. The name of each food found in the refrigerator, its location, packaging material, and expiration date will be recorded. During the in home interview, swabs of refrigerator surfaces will be collected from households for microbiological analysis. Several swabs will be taken from different locations, such as refrigerator handle, surface of shelves, meat drawers, vegetable bins, and locations where meat, vegetable, eggs, dairy or ready-to-eat foods are stored in the refrigerator. Food samples will be collected from participant's refrigerators for microbiological analysis. These samples will include home prepared foods, leftovers, opened packages, especially ready-to-eat foods, produce, and raw meat and poultry stored in the refrigerators. To assess the performance of home refrigerators and potential contamination by foodborne pathogens, we will determine the overall microbial contamination using Aerobic Plate Count and E. coli/Coliform Count, and Enterobacteriaceae Count as indicator microorganisms. In addition, measurements of prevalence of potential foodborne pathogens in the refrigerator will include Staphylococcus aureus, Bacillus cereus, and Clostridium perfringens from the samples of refrigerator surfaces and foods stored in the refrigerator. Presumptive colonies will be isolated and confirmed by biochemical and serological tests. Bacterial genomic DNA restriction patterns of the isolated bacteria will be analyzed using pulsed field gel electrophoresis. The incidence of cross contamination will be determined by fingerprinting strains of bacteria isolated from foods, containers, and refrigerator surfaces and by mapping the fingerprints for each strain of bacteria from the same refrigerator. Risky behavior exhibited by consumers will be determined and categorized by subpopulation groups. In response to the research findings, risk communication messages and education strategies for consumers will be developed.