Purpose: We investigated the survival of Salmonella, Escherichia coli O157:H7, and poliovirus on chili peppers at ambient temperatures, simulating some market conditions. Next, we investigated whether preserving by pickling or refrigeration affected pathogen survival rates.
Methods: Fresh bird chili peppers (Capsicum frutescens Linn.) were inoculated with a cocktail of Salmonella, E. coli O157:H7, and Poliovirus-1 and stored at 22 - 25°C. Separately, inoculated peppers were pickled (5% acetic acid vinegar, pH 2.54) and stored at 4°C for 8 weeks. Pathogens were enumerated from the fresh and pickled peppers (and the vinegar) initially and at days 1, 7, 28, and 56. Poliovirus was enumerated using the most probable number (MPN) infectivity assay. Salmonella and E. coli O157:H7 were enumerated on modified tryptic soy agar.
Results: Results validate the prolonged survival of pathogens on fresh and pickled bird chili peppers. Bacterial and viral pathogens showed differential trends in survival. On fresh peppers, Salmonella and E. coli O157:H7 remained relatively consistent (105 - 106 CFU/g) for 4 weeks at 25°C and significantly declined (P < 0.05) at week 8. Poliovirus numbers decreased significantly after 1 day and were undetectable at week 8. In contrast, no bacteria were recovered from pickled peppers and their vinegar following day one at 4°C. However, poliovirus persisted at significant levels on both pickled peppers and in their vinegar (103 MPN/g and 102 MPN/ml, respectively) for 8 weeks.
Significance: Results support the importance of preventing contamination of fresh produce during production and post-harvest. Additionally, results discredit the notion that common produce harvesting practices eliminate pathogens.