Purpose: This study investigated microbiological safety of fresh vegetables in pre-harvest and preprocessed vegetables in retail with regard to the farm-to-fork continuum.
Methods: Between April and November in 2012, a total of 107 samples (22 kinds) were collected from directly 53 farms grown (n = 53) and from 11 supermarkets (n = 54) in Gyeonggi-do, Korea. Aerobic plate count (APC), total coliforms (TC), Escherichia coli, Bacillus cereus, Clostridium perfringens, E. coli O157:H7, Salmonella spp. and Staphylococcus aureus were tested.
Results: The majority of APC, TC, B. cereus, C. perfringens and E. coli were in the range 5-7 log , 4-6 log , 1-2 log , 1-2 log and 1-3 log CFU/g, respectively. B. cereus was isolated in 29.0 % (n = 31), C. perfringens 14.0% (n = 15), E. coli 12.1% (n = 13). Lettuce (n = 4), crown dais (n = 1), green pepper (n = 3) from farms and washed celery (n = 1) from market found overlapped bacterial contamination. E. coli O157:H7, Salmonella spp., and Staphylococcus aureus were not detected in any of the samples analyzed. The highest contamination level of APC and TC was observed on washed root vegetables (bonnet bellflower, balloon flower, ginger). Leafy green vegetables from farms were highly contaminated with B. cereus 75.0% (n=15), C. perfringens 25.0% (n = 5) and E. coli 30.0% (n = 6). All C. perfringens isolated (n = 15) revealed CPA by analyzing real-time PCR. Compared microbial populations between preharvest and preprocessed samples, APC, TC and E. coli were not different (P > 0.05), while the prevalence of B. cereus and C. perfringens were lower in preprocessed samples (P< 0.05). Even washed products may contain pathogenic microorganisms and represent potential microbiological hazard.
Significance: This study provides basic database about microbiological quality of vegetables during growing and marketing in Korea.