TY - JOUR TI - Understanding and managing risk of norovirus contamination on frozen berries from farm to fork DO - https://doi.org/doi:10.7282/t3-hd84-7k88 PY - 2019 AB - Norovirus is the leading cause of acute gastroenteritis worldwide. Consumption of frozen berries have been identified as a risk factor for norovirus illness. This dissertation studies four scenarios that affect the risk of norovirus on frozen berries: the effect of freezing and frozen storage on the survival of bacteriophage MS2 (a norovirus surrogate) on frozen strawberries and raspberries; thermal inactivation kinetics of MS2 on frozen strawberry and raspberry purées in a water bath; efficacy of microwave heating on the destruction of MS2 in frozen strawberries; and an agent-based model simulating fruit pickers on a farm to quantify the spread of norovirus from an ill worker to coworkers and berries. The results show that bacteriophage MS2 is able to survive frozen storage on frozen berry products over long periods of time; heating of frozen berries following the product’s label instructions using the Defrost microwave oven setting resulted in minimal inactivation of MS2; and increased handwashing compliance on farm had a significant effect on the contamination of berries prior to reaching the consumer and an overall decrease in ill consumers. A quantitative microbial risk assessment was also developed to assess the risk of norovirus associated with consumption of frozen strawberries. A 2012 norovirus outbreak in Germany linked to frozen strawberries was simulated using the model. Model predictions were in good agreement with data from the actual outbreak. The risk assessment model developed may provide useful quantitative data relevant for risk management initiatives, aimed at controlling the risk of norovirus from frozen berry products. The research presented in this proposal was funded in part by the USDA-NIFA Food Virology Collaborative, NoroCORE (Norovirus Collaborative for Outreach, Research and Education) – a food safety initiative with the goal to reduce the burden of foodborne disease associated with noroviruses. KW - Food Science KW - Norovirus KW - Fruit -- Contamination -- Risk assessment KW - Frozen berries LA - English ER -