Cross-Contamination to Surfaces in Consumer Kitchens with MS2 as a Tracer Organism in Ground Turkey Patties.

ABSTRACT: It is estimated that one in five cases of foodborne illnesses is acquired in the home. However, how pathogens move throughout a kitchen environment when consumers are preparing food is not well characterized. The purpose of this study was to determine the prevalence and degree of cross-contamination across a variety of kitchen surfaces during a consumer meal preparation event. Consumers (n = 371) prepared a meal consisting of turkey patties containing the bacteriophage MS2 as a tracer organism and a ready-to-eat lettuce salad. Half were shown a video on proper thermometer use before the trial. After meal preparation, environmental sampling and detection were performed to assess cross-contamination with MS2. For most surfaces, positivity did not exceed 20%, with the exception of spice containers, for which 48% of the samples showed evidence of MS2 cross-contamination. Spice containers also had the highest MS2 concentrations, at a mean exceeding 6 log viral genome equivalent copies per surface. The high level of MS2 on spice containers drove the significant differences between surfaces, suggesting the significance of spice containers as a vehicle for cross-contamination, despite the absence of previous reports to this effect. The thermometer safety intervention did not affect cross-contamination. The efficiency of MS2 transfer, when expressed as a percentage, was relatively low, ranging from an average of 0.002 to 0.07%. Quantitative risk assessment work using these data would aid in further understanding the significance of cross-contamination frequency and efficiency. Overall, these data will help create more targeted consumer messaging to better influence consumer cross-contamination behaviors.

Observational Study of the Impact of a Food Safety Intervention on Consumer Poultry Washing.

ABSTRACT: This study was conducted to test the effectiveness of a consumer poultry washing educational intervention that included video observation of meal preparation with participants who self-reported washing poultry. Treatment group participants received three e-mail messages containing information that the U.S. Department of Agriculture has used on social media sites (video and infographics) related to poultry preparation, including advising against washing chicken. Participants were observed cooking chicken thighs (inoculated with traceable nonpathogenic Escherichia coli strain DH5α) and preparing a salad to determine whether they washed the chicken and the extent of cross-contamination to the salad and areas of the kitchen. After meal preparation, participants responded to an interview about food handling behaviors, including questions about the intervention for treatment group participants. Three hundred people participated in the study (158 control, 142 treatment). The intervention effectively encouraged participants not to wash chicken before cooking; 93% of treatment group participants but only 39% of control group participants did not wash the chicken (P < 0.0001). The high levels of E. coli DH5α detected in the sink and on the salad lettuce suggest that microbes transferred to the sink from the chicken, packaging, or contaminated hands are a larger cause for concern than is splashing contaminated chicken fluids onto the counter. Among chicken washers, 26 and 30% of the lettuce from the prepared salad was contaminated for the control and treatment groups, respectively. For nonwashers, 31 and 15% of the lettuce was contaminated for the control and treatment groups, respectively. Hand-facilitated cross-contamination is suspected to be a factor in explaining this resulting lettuce cross-contamination. This study demonstrates the need to change the frame of "don't wash your poultry" messaging to instead focus on preventing contamination of sinks and continuing to emphasize the importance of hand washing and cleaning and sanitizing surfaces.

An Observational Study of Thermometer Use by Consumers When Preparing Ground Turkey Patties.

ABSTRACT: The purpose of this study was to test the effectiveness of an intervention for consumer thermometer use by using a randomized experimental design and direct observation of meal preparation. The study was conducted in test kitchen facilities in two locations in North Carolina (one urban and one rural). Cameras recorded participants' actions at various locations throughout the kitchen and recorded the meal preparation from beginning to end. Before preparing the meal, a randomized treatment group watched a 3-min U.S. Department of Agriculture (USDA) food safety video "The Importance of Cooking to a Safe Internal Temperature and How to Use a Food Thermometer." Participants in the control and treatment groups were observed while cooking turkey burgers and preparing a salad to determine whether a thermometer was used to check the doneness of the turkey patties. Following meal preparation, all participants responded to a postobservation interview about food handling behaviors. Treatment group participants were also asked about the intervention. A total of 383 people participated in the study (201 in the control group and 182 in the treatment group). Participants who viewed the video were twice as likely to use a thermometer to check the doneness of the turkey patties compared with the participants who were not exposed to the video (75 versus 34%) and twice as likely to place the thermometer in the correct location (52 versus 23%). Sixty-seven percent of participants who watched the video reported that it influenced their behavior in the kitchen. This study demonstrates the importance of timing and framing of a behavioral intervention for thermometer use and highlights considerations for the development of additional messages (e.g., proper insertion).