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This study was conducted to investigate the effects of aerosolized malic acid and ultraviolet light (UV‐C) for inhibiting the growth of foodborne pathogens, Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes, on fresh‐cut lettuce. The antimicrobial effects of aerosolized 2% malic acid and UV‐C, alone or in combination, were tested. Ten grams of lettuce were inoculated with three strains of each pathogens and treated with aerosolized malic acid for 20 min and UV‐C for 30 min. After each treatment, lettuce was stored at 5 °C for 15 days. Sequential treatment (aerosolized malic acid after UV‐C) was the most effective for reducing E. coli O157:H7, S. Typhimurium, and L. monocytogenes and resulted in reduction of 2.89, 1.38, and 2.95 log10 CFU/g after treatment and 3.15, 3.00, and 4.58 log10 CFU/g after 15 days, respectively. These results suggested that combined treatment with aerosolized malic acid after UV‐C can be a useful intervention method for improving the microbial safety of fresh‐cut produce. Practical applications The experiment suggested new method on the inactivation of foodborne pathogens on lettuce. Treatment with aerosolized 2% malic acid after UV‐C was the most effective method to inhibit the growth of foodborne pathogens in this study. This method will be helpful for fresh‐cut lettuce producers to manage the safety and quality of lettuce.

This study investigated the antimicrobial activity of malic acid (MA), grapefruit seed extract (GSE), and combined (MA+GSE) treatment against O157:H7, Typhimurium, and on fresh-cut lettuce. The antimicrobial effects of 1% MA and 0.5% GSE alone and in combination (1% MA+0.5% GSE) were tested on artificially inoculated lettuce during storage at 5°C for 14 days. The maximum reductions of O157:H7, S. Typhimurium, and were 4.96, 4.80, and 3.95 log CFU/g observed with MA+GSE during storage for 14 days, respectively. MA+GSE showed the greatest reduction against in O157:H7 and . These results indicate that the combined treatment was more effective than MA and GSE alone treatment. Therefore, it suggests that MA + GSE could be used as an effective intervention method for improving microbiological safety of fresh-cut lettuce.

This study was conducted to assess the possibility of preserving frozen vegetables (Aster scaber, soybean sprouts, Chinese cabbage, green pumpkin, and Welsh onion) for a long period and of using them after such storage by measuring changes in quality due to their preservation. Various freshly harvested vegetables were blanched under optimal conditions (that were determined in a preliminary experiment), quick-frozen at -40℃ for 24 h, and stored at -20℃. The change in the chromaticity of the frozen A. scaber, soybean sprouts, Chinese cabbage, green pumpkin, and Welsh onion did not vary. The hardness of the frozen A. scaber, green pumpkin, Chinese cabbage and Welsh onion did not change during the preservation period, whereas the hardness of the cotyledon and hypocotyl of the soybean sprouts significantly increased on the sixth month of their storage. The total bacterial counts of the A. scaber during the preservation period remained constant at 10 3 CFU/g, whereas those of soybean sprouts, Chinese cabbage, green pumpkin, and Welsh onion decreased slightly to 10 2 CFU/g. Coliform was not detected in any of the samples. The sensory evaluation showed that the preservation period that was used in this study did not significantly affect the marketability of the frozen vegetables. Therefore, it was considered that A. scaber, soybean sprouts, Chinese cabbage, green pumpkin, and Welsh onion can be safely preserved by freeze-storing them for up to 12 months.