• Korean Journal of Microbiology
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• v.47 no.4
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• pp.335-341
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• 2011

In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.

• Journal of environmental and Sanitary engineering
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• v.22 no.3
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• pp.35-50
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• 2007

In order to investigate water pollution of spring, we carried out the experiments on mineral water, rainwater and surrounding soil of several springs collected in Incheon area from February to August in 2007. The results were as follows. 1. Soil : This study investigated the pH and organic matter contents in the soil which effect on microorganisms. The pH value was from 4.5 to 5.3 on average and organic matter contents ranged from 1.09% to 5.6% and E. coli, K. pneumoniae, S. faecalis and other microorganisms were isolated. 2. Natural mineral water : As the rainfall increased, the concentration of $No_3-N$, consumption of $KMnO_4$ and the number of microorganisms was increased while the other physicochemical items were not affected. The microorganism isolated in the natural mineral water were as follows: E. coli, K. oxytoca S. faecalis, S. facium, and so on from evacuation; E. agglomerans, E. amnigenus, E. cloacae, E. sakazakii and so on from the environments and evacuation. Detection of these microorganisms shows that the environment around the spring had been exposed to excrements of the warm blood animal. 3. Rain : The coliforms in the rain were the identical one detected from the mineral water and the soil. In conclusion the quality of natural mineral water is influenced by rain, resident bacteria of soil and surrounding environment. This study will be the basic data of characteristics of spring in Incheon area and also this result will give useful aids for the efficient control of spring.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.161-168
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• 2011

The purpose of this study was to evaluate microbiological contamination of fresh vegetables in Korea. Twenty types of vegetables were tested for total aerobic bacteria, coliforms, Escherichia coli, yeast and mold, and pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Salmonella, E. coli O157:H7, Cronobacter sakazakii, Shigella, and Campylobacter. Levels of total aerobic bacteria and coliform on 20 vegetables were between 3.74 and 8.04 log CFU/g, and 0.16 and 5.02 log CFU/g, respectively. The highest contamination levels of total aerobic bacteria were observed on water dropwort, sprouts, mungbean sprout, and ballflower root. There was no significant difference (p>0.05) in microbial contamination levels of total aerobic count, coliform, E. coli, yeast and mold between organic and nonorganic vegetables. When isolation methods using selective agars were applied, L. monocytogenes, B. cereus, Salmonella and Campylobacter were isolated from some fresh vegetable samples. Results of API kit tests showed that L. monocytogenes was identified on Chinese cabbage, cucumber, soybean sprouts, and iceberg lettuce while Salmonella was identified on Korean leek. Furthermore, Campylobacter jejuni was also identified in more than 50 of the 100 samples. However, when positive samples from API kit were tested for real-time PCR or 16S rRNA sequencing method, only B. cereus from perilla leaf, carrot, water dropwort, and sprouts showed positive results. These results indicate that selective agar and API kit detection methods might result in false positive results for some pathogens. Therefore, studies need to improve isolation or confirmation methods for such pathogens.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.555-561
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• 2008

Ninety-nine samples of powdered infant formula in a market were collected from the local market and their contaminations for total aerobic bacteria, coliform, FAO/WHO Category A, B, and C pathogens were analyzed. Total aerobic bacteria were detected in 92 of 99 samples (93%) at levels of $1.83{\pm}0.68\;Log\;MPN/g$. These levels were below legal levels specified for infant formulas except for one sample detected by 4.5 Log CFU/g. Coliform was detected in 12 of 99 samples (12%) at levels of $1.26{\pm}1.03\;Log\;MPN/g$ whereas non-detection was required according to the specification of coliform in infant formulas. Escherichia coli was detected in 1 of 99 samples by 0.48 Log MPN/g. Salmonella and Enterobacter sakazakii among Category A weren't detected in all the samples. Enterobacteriaceae, Category B group, were detected in 25 samples of total 99 samples (25%) by $0.83{\pm}1.37\;Log\;MPN/g$. Enterobacteriaceae identified by API 20E were Escherichia vulneris, Es. hermannii, Pantoea spp., Citrobacter koseri, Klebsiella pneumoniae, En. cloaceae. Bacillus cereus among Category C was highly detected in 29 of 99 samples (29%) at levels of $0.69{\pm}0.32\;Log\;MPN/g$ with the most probable number count method, which were below legal levels for the specification of B. cereus in infant formulas. Clostridium perfringens, E. coli O157, Staphyloccus aureus, Listeria monocytogenes, Yersinia enterocolitica, and Campylobacter jejuni/coli were not detected. Contamination level of major pathogens was low and falls within the range of specification of infant formulas. However, Enterobacteriaceae and B.cereus showed the high prevalence and some Enterobacteriaceae causing disease were detected. Therefore, it is necessary to monitor the potential pathogens continually and reduce them to improve the microbial quality of non-sterilized powdered infant formulas.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.35-43
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• 2013

The substances of lactic acid bacteria (LAB) isolated feom Kimchi and Tarak, L. mesenteriodes LAB kw5, and S. thermophilus LAB KW15 were investigated for growth effect of Helicobacter pylori with IgY and Auricularia auricula. Inhibition of H. pylori was confirmed at LAB KW5 and KW15 supernatants. Interestingly, anti-H. pylori substance in LAB KW5 and KW15 supernatants were sensitive to lipase, but insensitive to protein hydrolase and carbohydrate hydrolase. The inhibition zone toward H. pylori was not shown with the lipase-treated supernatants. Therefore, there seemed to be lipid-like substances in the cultures. By the analyses with gas chromatography, undecanoic acid ($C_{11:0}$), palmitic acid ($C_{16:0}$), stearic acid ($C_{18:0}$), and oleic acid ($C_{18:1}$) were detected at the culture substances from L. mesenteroides LAB KW5 and S. thermophilus LAB KW15, and more eicosadienoic acid ($C_{20:2}$) from L. mesenteroides LAB KW5. Anti-H. pylori substances of LAB with IgY and A. auricula extract were analyzed for inhibition effect of H. pylori. The inhibition increased more by the range from 57% to 86% by the mixture. The substances with IgY and A. auricula extract showed more effective inhibition of H. pylori than single or double trials.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.1-12
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• 2015

This study was performed to determine risk ranking of the combination of pathogen-livestock or livestock products to identify the most significant public health risks and to prioritize risk management strategies. First, we reviewed foodborne outbreak data related to livestock products and determined main vehicles and pathogens according to the number of outbreak and case. Second, expert's opinion about management priority of pathogen-livestock product pairing was surveyed with 19 livestock experts in the university, research center, and government agency. Lastly, we used the outcome of Risk Ranger (semi-quantitative risk ranking tool) of 14 combinations of pathogen and livestock or livestock products. We have classified the combination of pathogen-livestock products into group I (high risk), II (medium risk), and III (low risk) according to their risk levels and management priority. Group I, which is the highest risk for foodborne outbreak, includes Salmonella spp./egg and egg products, Campylobacter spp./poultry, pathogenic E. coli/meat and processed ground meat. In conclusion, the results of this study will provide the specific guideline of mid- and long-term planning for risk assessment and risk management prioritization of the combination of pathogen and livestock, or livestock product.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1214-1221
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• 2008

The aim of this study is to propose suggestions for establishing Korean regulatory standards of infant formula. Accordingly, the regulatory standards for food contaminants and additives in Korean infant formulas were compared and analyzed with those in CODEX, EU, Australia and New Zealand. Several suggestions for regulations were found from different countries. Firstly, it is advisable that additives for nutrient supplement of infant formula be classified as types of nutrients. Secondly, it is proposed that guidelines should be set on the maximum amount of additives in infant formula. Thirdly, pathogens such as Staphylococci and Salmonella of infant formula should be regulated. Finally, present regulations need to establish the maximum permissible levels of some pesticides, Pb and Al, that other countries are already regulating. These proposed recommendations would broaden the scope of infant formula regulatory standards needed for infants' health.