Purpose: To determine the levels of microbial contamination of fruits and vegetables during the production chain in northeast Mexico.
Methods: In this study, 4 tomato farms, 7 jalapeño farms and 3 cantaloupe farms were screened. A total of 55 samples of soil, 89 samples of irrigation and source water, 161 samples of produce and 106 samples of hand rinse from farm workers were collected during the harvest season. Levels of coliforms, Enterococcus, and E. coli were analyzed using filtration methods, and commercial kits. Salmonella spp. and E. coli O157:H7, were assayed by BAM procedures.
Results: Statistically significantly (P < 0.05) higher levels of indicator bacteria, compared to soil and water samples, were found in hand rinse samples. In hand rinse samples, levels of coliforms ranged from 1 x 103 to > 1.5 x 104 CFU/ml, and levels of Enterococcus ranged from < 1 to > 5 x 104. Among produce, coliforms ranged from 4 x 102 to > 1.5 x 104 and < 1 to 5 x 105 CFU/ml for Enterococcus. Cantaloupes had significantly higher levels of indicator bacteria compared to tomatoes and jalapeños. Levels of E. coli were very low (< 5 CFU/ml) in water samples, however in hand rise samples levels of E. coli were significantly higher. Salmonella was found in one sample of melon and E. coli O157:H7 was found in one jalapeño pepper. Water and soil samples showed moderate levels of indicator organisms.
Significance : Cantaloupes exhibited higher contamination and hands are a potential source of contamination. Intervention approaches during the production chain are necessary to reduce the risk of infection in consumers.