Bacillus cereus contamination is a major food safety problem for Korean fermented soybean products, but few studies have assessed its potential to cause foodborne illness. The objectives of this study were to investigate the prevalence and characteristics of B. cereus isolated from Korean fermented soybean products. B. cereus was detected in 110 of 162 (67.9%) samples. The highest B. cereus frequency was observed in deonjang (68 of 93 samples, 73.1%) and cheonggukjang (18 of 25, 72.0%); however, nonhemolytic enterotoxin was detected only in 22 of 162 samples (13.6%). Although the tested B. cereus isolates showed diverse pulsotypes according to repetitive sequence-PCR banding patterns, they displayed similar antibiotic sensitivity spectra. The low frequency of enterotoxin detection suggests that the potential risk of B. cereus foodborne illness associated with Korean fermented soybean products is lower than generally presumed. However, considering the prevalence of B. cereus and the high content of fermented soybean products in the Korean diet, it is necessary to constantly monitor the level of contamination with B. cereus and its toxins in such Korean food products.

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Bacillus thuringiensis microbial insecticide products have been applied worldwide. Although a few cases of B. thuringiensis foodborne illness have been reported, little is known about the toxigenic properties of B. thuringiensis isolates. The aims of this study were to estimate the pathogenic potential of B. thuringiensis selected from microbial insecticide products, based on its possession of toxin genes and production of enterotoxins. Fifty-two B. thuringiensis strains selected from four kinds of microbial insecticide products were analyzed. PCR assay for detection of toxin genes and immunoassay for detection of enterotoxins were performed. The hemolysin BL complex as a major enterotoxin was produced by 17 (32.7%), whereas the nonhemolytic enterotoxin complex was detected in 1 (1.9%) of 52 B. thuringiensis strains. However, cytK, entFM, and ces genes were not detected in any of the tested B. thuringiensis strains. The potential risk of food poisoning by B. thuringiensis along with concerns over B. thuringiensis microbial insecticide products has gained attention recently. Thus, microbial insecticide products based on B. thuringiensis should be carefully controlled.

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Surveys on the consumption of caffeinated beverages by high school students (n=886) were performed. Of the students, 97.0% consumed a variety of caffeinated beverages, including carbonated drinks (90.0%), processed milk and cocoa (79.0%), coffee (63.0), teas (52.1), energy drinks (16.4%) and nourishment drinks (15.5%). The frequency of intake per student was 8.2 times per week. Caffeine intake through the caffeinated beverages was 41.53 mg/day, which was accounted for by coffee (51.5%), carbonated drinks (19.6%), processed milk and cocoa (11.5%), teas (11.4%), energy drinks (5.0%) and nourishment drinks (1.1%). Students with high levels of stress, those who consumed snacks twice a day, and those who used a computer (or smart phone) for more than 3 hours per day showed significantly higher caffeine intake. The groups with high caffeine intake experienced heart palpitations, insomnia and pollakiuria. Students indicated that they consumed the caffeinated beverages for the taste (57.9%), waking up (18.0%), thirst (13.2%), etc. (10.9%). They tended to consume drinks with a high content of caffeine to sleep less. In addition, they rarely checked the label, and showed a lack of awareness of the caffeine contents in the beverages, which calls for education.

This study was conducted to investigate the phenotypic and genotypic characteristics of Korean isolates of Cronobacter spp. (Enterobacter sakazakii). A total of 43 Cronobacter spp., including 5 clinical isolates, 34 food isolates, 2 environmental isolates, and 2 reference strains (C. sakazakii ATCC 29004 and C. muytjensii ATCC51329) were used in this study. Korean isolates of Cronobacter spp. were divided into 11 biogroups according to their biochemical profiles and 3 genomic groups based on the analysis of their 16S rRNA gene sequences. Biogroups 1 and 2 contained the majority of isolates (n=26), most of which were contained in 16S rRNA cluster 1 (n=34). Korean isolates of Cronobacter spp. showed diverse biochemical profiles. Biogroup 1 contained C. sakazakii GIHE (Gyeonggido Research Institute of Health and Environment) 1 and 2, which were isolated from babies that exhibited symptoms of Cronobacter spp. infection such as gastroenteritis, sepsis, and meningitis. Our finding revealed that Biogroup 1, C. sakazakii, is more prevalent and may be a more pathogenic biogroup than other biogroups, but the pathogenic biogroup was not represented clearly among the 11 biogroups tested in this study. Thus, all biogroups of Cronobacter spp. were recognized as pathogenic bacteria, and the absence of Cronobacter spp. in infant foods should be constantly regulated to prevent food poisoning and infection caused by Cronobacter spp.

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 ± 0.38 log 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.

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