• Journal of Food Hygiene and Safety
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• v.39 no.4
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• pp.335-342
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• 2024

This study aimed to examine the delivery conditions and microbial contamination of fresh-cut and ready-to-eat foods purchased from online markets between February and November 2023. Upon arrival, the average surface temperature of the products was 11.3℃. In the fresh-cut foods, the average number of total aerobic bacteria and coliforms was 4.5 log colony-forming units (CFU)/g and 1.2 log CFU/g, respectively, whereas in the ready-to-eat foods, these values were 10.6 log CFU/g and 1.2 log CFU/g, respectively. Pathogens, such as Staphylococcus aureus, Salmonella spp., Clostridium perfringens, Listeria monocytogenes, and pathogenic Escherichia coli were absent from all samples. Bacillus cereus was found in 2.7% of the fresh-cut foods and 0.9% of the ready-to-eat foods, with contamination levels averaging 0.05 log CFU/g and 0.01 log CFU/g, respectively. In the four samples in which B. cereus was detected, genetic testing of the six toxin genes produced by B. cereus revealed the presence of at least one enterotoxin gene, excluding the emetic toxin. L. monocytogenes was absent from ready-to-eat foods but was detected in 0.9% of fresh-cut foods. Analysis of the isolated L. monocytogenes confirmed the presence of six pathogenicity-related genes, including iap, indicating the potential risk of foodborne diseases.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.799-808
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• 2021

This study was performed to investigate the extent of microbial contamination, the presence of enterotoxin genes, and the antibiotic susceptibility of Bacillus cereus in 58 red pepper plants and 43 environmental samples (soil, irrigation water, and gloves) associated with the plant cultivation. The detected counts of total aerobic bacteria, coliform bacteria, Escherichia coli, Bacillus cereus, and Staphylococcus aureus were lower in these samples, as compared to the regulations of standards for foods; moreover, pathogens, such as E. coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp., were not detected. Genes encoding hemolysin BL enterotoxins (hblA, hblC, and hblD) as well as non-hemolytic enterotoxins (nheA, nheB, and nheC) were detected in 23 B. cereus specimens that were isolated from the test samples and had β-hemolytic activity. Interestingly, B. cereus is resistant to β-lactam and susceptible to non-β-lactam antibiotics. However, in this case, the isolated B. cereus specimens exhibited a shift from resistant to intermediate in response to cefotaxime and from susceptible to intermediate in case of rifampin, trimethoprim-sulfamethoxazole, vancomycin, clindamycin, and erythromycin. Therefore, the levels of B. cereus should be monitored to detect changes in antibiotic susceptibility and guarantee their safety.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.30-36
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• 2012

This study was conducted to evaluate the microbiological hazard on nursery school children's hands and to investigate the reduction effect of hand washing education. A total of 59 nursery school children's hands were tested. The average number of total aerobic bacteria was $3.72{\pm}0.38log\;CFU/hand$. Five children's hands(2 male and 3 female) were positive(14.3%) for the coliform bacteria. These results showed that hand washing education are required repetitively. Among the pathogenic bacteria tested in this study, $Staphylococcus$ aureus and $Bacillus$ $cereus$ were detected in 9(25.7%) and 16(45.7%) out of 35 their hands, respectively. Twelve out of sixteen $B.$ $cereus$ isolates(70.0%) produced enterotoxin. The results indicate that the hand hygiene of nursery school children needs to be improved. Comparing before and after hand washing in educated and non-educated group, the reduction effect of total aerobic bacteria on their hands was 0.42 and 0.60 log CFU/hand, respectively. The educated group showed 0.18 log CFU/hand higher reduction effect than non-educated group but microorganism did not eliminate perfectly. From the results, using a hand sanitizer after washing with soap and the continuous hand washing education are required to control the contaminated bacteria on nursery school children's hands.