Analysis of Microbiological Contamination in Cultivation and Distribution Stage of Melon

The purpose of this study was to evaluate microbial contamination of melons in Korea. A total of 123 samples including melon fruits, leaves, seeds, soils, and irrigation water were collected from farms and markets to detect total aerobic bacteria, coliform, Escherichia coli, and pathogenic bacteria such as Bacillus cereus, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus. Samples were collected from Iksan and Nonsan farms to monitor bacterial levels on pre-market melons. The total aerobic and coliform bacteria on melon cultivation were between 0.43 and 6.65 log CFU g -1 , and 0.67 and 2.91 log CFU g -1 , respectively. Bacillus cereus, a fecal coliform, was detected in soils and melon leaves from Iksan farm at 2.95, 0.73 log CFU g -1 , respectively, and in soils from Nonsan farm at 3.16 log CFU g -1 . Market melon samples were collected to assay bacterial load on melon being sold to consumers. The contamination levels of total aerobic bacteria in agricultural markets, big-box retailers, and traditional markets were 4.82, 3.94, 3.99 log CFU g -1 , respectively. The numbers of coliform in melon on the markets ranged from 0.09 to 0.49 log CFU g -1 . Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus were not detected in any samples. The count of total aerobic bacteria on melon seeds ranged from 0.33 to 3.34 log CFU g -1 . This study found that irrigation water, soil, manure and various farm work activities including post-harvest processes were latent sources of microbial contamination. These results suggest that hygienic management and monitoring of soil, water, and agricultural material should be performed to reduce microbial contamination in melon production.