Socioecological Factors Interact to Drive Differences in Hygiene Indicator Load on Retail Fresh Produce Available to...

Food safety at neighborhood stores may differ for communities of distinct socioeconomic strata, but such differences are underexplored. We aimed to characterize microbial contamination (MC) on fresh produce available to Athens, GA communities (k = 2) of diverse socioeconomic composition. MC was assessed as a function of the main effects of season, store type, and community, and their 2- and 3-way interactions. Cucumbers, lettuce, and tomatoes (144 each) from groceries, supermarkets, and superstores - collected over winter and summer from each community - were tested for generic Escherichia coli, coliforms, and Salmonella enterica using culture-based methods. Presumptive S. enterica colonies (n = 338) were identified with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. No S. enterica was detected, and predominant off-target genera showed trends per the isolation media used. Generic E. coli load was below the countable range for all samples. Mean coliform load (MCL) variation on cucumbers was driven by the interaction of community and store type (P < 0.01) and that of season and store type (P < 0.01). Higher resource community (HR) grocery cucumbers had greater MCL, 4.00 log CFU/g, than superstore cucumbers, 3.07 log CFU/g. Lower resource community superstore cucumbers had greater MCL, 3.04 log CFU/g, than grocery cucumbers, 2.05 log CFU/g. Superstore cucumbers had greater MCL, 3.46 log CFU/g, than grocery cucumbers, 2.45 log CFU/g in summer. In winter, superstore cucumbers had lower MCL, 2.66 log CFU/g, than grocery cucumbers, 3.60 log CFU/g. MCL variation on lettuce was driven by the interaction of community and store type (P < 0.01). MCL on lettuce from HR groceries and superstores, 1.86 log CFU/g and 1.42 log CFU/g, respectively, was greater relative to supermarkets, 0.96 log CFU/g. These findings show that season, the built food environment, and community context interact to drive coliform load differences on retail produce available to Athens communities.