Persistence of Foodborne Pathogens on Farmers' Market Fomites

The number of farmers' markets registered by the U.S. Department of Agriculture has seen a significant increase, jumping from 1,755 in 1994 to 8,771 in 2019. Although previous studies have investigated the microbial profile of produce obtained from farmers' markets, literature exploring microbial (bacteria and virus) persistence on a variety of different farmers' market fomites over a 2-month period is limited. The objective of the current study was to investigate the persistence of key foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and MS2 bacteriophage) on these fomites by using a microbiological viability assay. The MS2 bacteriophage was quantified by using a host E. coli strain, and PFU were identified. A repeated measures analysis of variance was used to compare the persistence rates of foodborne pathogens on cardboard, plastic, tablecloth, molded pulp fiber, and wicker baskets used to store, transport, and display produce at farmers' markets. In general, molded pulp fiber, plastic, and wicker surface materials supported the persistence of foodborne pathogens the most, with Salmonella and S. aureus demonstrating the highest log concentrations over the longest period of time. Additionally, E. coli strains also persisted for a significant period of time on all fomites, with the exception of tablecloth. The results suggest that foodborne pathogens on these fomites pose a high risk of cross-contamination, particularly if the fomites cannot be washed, rinsed, and sanitized effectively (e.g., cardboard). The results highlight the need to avoid using porous, single-use storage containers, such as cardboard, molded pulp fiber, and wicker containers for extended periods of time and suggest the use of easily cleanable materials, such as plastic containers.