• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.296-303
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• 2005

A strain named as HJ35 was isolated from the skin of sixty-five men and fourteen women for acne therapy, in order to find an effective antimicrobial agent against Propionibacterium acnes. Isolate HJ35 was identified as Enterococcus faecium based on 16 rDNA sequence and produced enterocin HJ35 having antimicrobial activities against most lactic acid bacteria, En­terococcus spp., Staphylococcus aureus, S. epidermidis, Clostridium perfringens, some bacilli, Mi­crococcus flavus, Listeria monocytogenes, L. ivanovii, Escherichia coli, Pseudomonas fluorescens and Propionibacterium acnes, in the modified well diffusion method. Especially, enterocin HJ35 showed a bactericidal activity against Propionibacterium acnes P1. The antimicrobial activity of enterocin HJ35 was disappeared completely with the use of protease XIV. But enterocin HJ35 activity is very stable at high temperature (up to $100^{\circ}C$ for 30 min), in wide range of pH (3.0${\~}$9.0), and by treatment with organic solvents. The apparent molecular mass of enterocin HJ35 was estimated to be approximately 4${\~}$4.5 kDa on detection of its bactericidal activity after SDS-PAGE. In batch fermentation of E. faecium HJ35, enterocin HJ35 was produced at the mid­log growth phase, and its maximum production was obtained up to 2,300 AU/mL at the late stationary phase. By employing fed-batch fermentation, the enhanced production of enterocin HJ35 was achieved up to 12,800 AU/mL by feeding with 10 g/L glucose or 6 g/L lactate.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.697-706
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• 2018

Lactobacillus pentosus K1-23 was selected from among 25 lactic acid bacterial strains owing to its high inhibitory activity against several pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, S. gallinarum, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium perfringens, and Listeria monocytogenes. Additionally, among 13 strains of Aureobasidium spp., A. pullulans NRRL 58012 was shown to produce the highest amount of ${\beta}$-glucan ($15.45{\pm}0.07%$) and was selected. Next, the optimal conditions for a solid-phase mixed culture with these two different microorganisms (one bacterium and one yeast) were determined. The optimal inoculum sizes for L. pentosus and A. pullulans were 1% and 5%, respectively. The appropriate inoculation time for L. pentosus K1-23 was 3 days after the inoculation of A. pullulans to initiate fermentation. The addition of 0.5% corn steep powder and 0.1% $FeSO_4$ to the basal medium resulted in the increased production of lactic acid bacterial cells and ${\beta}$-glucan. The following optimal conditions for solid-phase mixed culture were also statistically determined by using the response surface method: $37.84^{\circ}C$, pH 5.25, moisture content of 60.82%, and culture time of 6.08 days for L. pentosus; and $24.11^{\circ}C$, pH 5.65, moisture content of 60.08%, and culture time of 5.71 days for A. pullulans. Using the predicted optimal conditions, the experimental production values of L. pentosus cells and ${\beta}$-glucan were $3.15{\pm}0.10{\times}10^8CFU/g$ and $13.41{\pm}0.04%$, respectively. This mixed culture may function as a highly efficient antibiotic substitute based on the combined action of its anti-pathogenic bacterial and immune-enhancing activities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.243-249
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• 2017

Crabs are a popular seafood item. However, they can harbor many microorganisms, heavy metals, radioactivity, and benzo(a)pyrene, which are potential health risks to humans. The objective of this study was to assess the potential of swimming crabs for use in foods such as Ganjang-gejang, by measuring their sanitary biological and chemical properties. Viable microbial cell counts in swimming crab samples were $3.4{\times}10^2-6.7{\times}10^4CFU/g$, but no coliform, Escherichia coli, or pathogenic bacteria, such as Vibrio parahaemolyticus, Enterohemorrhagic E. coli, Listeria monocytogenes, Staphylococcus aureus, or Salmonella spp., were detected. Heavy metal concentrations in swimming crab samples were non-detectable to 0.112 mg/kg for total mercury, non-detectable to 0.435 mg/kg for lead, and 0.115-0.836 mg/kg for cadmium. Benzo(a)pyrene concentrations ranged from $0.025-0.060{\mu}g/kg$, and the volatile basic nitrogen content ranged from 8.7-15.6 mg/100 g. No radioactivity was detected in samples. These results suggest that swimming crabs are viable for use in seafood products.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.41-47
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• 2003

In this study, antibacterial activity on the chicken feed supplemented with different concentrations of oriental herbal medicine feed additives (OHMFA) extract was tested for some organisms and their preventive effects on the colonization of Salmonella enteritidis (SE) in broiler chickens were examined. The growth of Bacillus cereus, listeria monocytogenes and Staphylococcus aureus was inhibited on the feed of 0.25% OHMFA and Salmonella spp. and Escherichia coli O157:H7 were inhibited on the feed containing 2.0% level. The broiler chickens fed a forage additived 1.0% level of OHMFA after inoculation of a $10^7CFU/ml$ of SE were increased in weight than the chicken fed forage without OHMFA. The incidence of SE in liver, spleen and cecum of the chickens fed forage with OHMFA was decreased on the 7th days of postinfection and SE was not isolated from the organs of the chickens after the 14th days of postinfection. Serum antibody titers of the chickens were lowered than the control group.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.785-790
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• 2013

The purpose of this study was to investigate the hazards from onions and their cultivation areas. A total of 32 samples were collected from onion farms and tested for biological (sanitary indicators, and pathogenic bacteria and fungi) and chemical (heavy metals and pesticide residues) hazards. Aerobic bacteria and coliforms were detected at a level of 0.2-7.1 log CFU/g (or mL) in the soil and agricultural water, 1.6-3.6 log CFU/g on surface of the onion, 0.0-6.0 log CFU/hand (or $cm^2$) on the workers' hands, clothes, and gloves, and 4.7 log $CFU/cm^2$ on the onion bags. Fungi were detected at a level of 0.0-5.0 log CFU/g (or mL, hand, or 100 $cm^2$) in all the samples. Staphylococcus aureus was detected at a level of 1.2 log CFU/hand on the workers' hands, the detection level of Bacillus cereus was up to 4.8 log CFU/g in the soil. However, Escherichia coli (and in particular strain O157:H7), Listeria monocytogenes, and Salmonella spp. were not detected. Although heavy metals were detected in the environment (in soil and agricultural water) and pesticide residues were detected in onion, the levels were lower than the regulation limits.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.533-540
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• 2016

This study assessed the risk of an oyster-shucking site to establish the hazard analysis critical control point (HACCP) system model by measuring viable cell counts, coliform group Staphylococcus aureus foreign material on oysters, oyster-producing equipment, and washing water. The viable cell count and coliform group levels of the harvested raw oysters were 4.00 log CFU/g and 1.1×10² MPN/100 g, while those of washed oysters were 2.99 log CFU/g and (3.2−4.6) × 10 MPN/100 g, respectively. After washing the oysters, no Escherichia coli or pathogenic bacteria (E. coli O157:H7, Listeria monocytogenes, S. aureus, Salmonella spp., Vibrio parahaemolyticus, and Clostridium perfringens) were detected. Regardless of the location of foreign matter, up to 100% more metallic and non-metallic foreign matter was detected at 1.5 mmΦ than at 3.5 mmΦ, using a metal detector with increased sensitivity. According to the results, the critical control points (CCP) are the washing and metal-detection processes. These results can be used as basic data to improve sanitation at oyster-shucking sites in factories with an HACCP system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.2
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• pp.121-126
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• 2018

The purpose of this study was to assess bacteriological hazards in the following 7 kinds of minimally processed shellfish products purchased from Korean seafood retail outlets: raw oysters stored with seawater in polyethylene bags, frozen oysters, raw mussels, frozen mussels, boiled mussels, raw short-necked clam, and frozen short-necked clams, obtained from Korean seafood retail outlets. The total coliform and Escherichia coli counts determined in all samples were detected below regulation limit of the Korean government guidelines (Food Code). In addition, the high-risk bacterial pathogens, Listeria monocytogenes, Salmonella spp., and E. coli O157:H7 were not detected in any samples. Low-risk pathogens such as Staphylococcus aureus and Vibrio parahaemolyticus were detected at levels above $1.0{\times}10^2$ colony forming unit (CFU)/g in some minimally processed shellfish products. Notably, S. aureus was detected in all samples. Raw oysters stored with seawater in polyethylene bags, frozen oysters, and boiled blue mussels are commonly ingested without heating, and therefore these minimally processed shellfish products pose bacteriological hazards. The detection of S. aureus in all shellfish products, an organism indicative of poor personal hygiene, which can grow and multiply during distribution, indicates the necessity of improving the food safety of minimally processed shellfish products.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.335-342
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• 2017

Oysters Crassostrea gigas are a globally popular shellfish for human consumption. As filter-feeding bivalve mollusks, oysters may harbor many microorganisms and chemicals that could pose potential human health risks. The objective of this study was to investigate the suitability of cultured oysters for raw consumption or use in seafood products by measuring concentrations of harmful microorganisms and chemicals in their flesh. Microbial concentrations in cultured oysters were found to be: $1.0{\times}10^2-6.0{\times}10^4CFU/g$ (viable cell counts), not detected $(ND)-5.4{\times}10^3CFU/g$ (coliform bacteria), $ND-1.3{\times}10^2CFU/g$ (E. coli), and $ND-4.6{\times}10^3CFU/g$ (Vibrio parahaemolyticus). Other pathogenic bacteria, including Enterohemorrhagic E. coli (EHEC), Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp., were not detected in any samples. Heavy metal concentrations of cultured oysters were ND-0.239 mg/kg (total mercury), ND-1.091 mg/kg (lead), ND-0.968 mg/kg (cadmium). The concentrations of benzo(a)pyrene ranged from $0.280-0.880{\mu}g/kg$. Paralytic shellfish poison ranged from ND-0.58 mg/kg, while diarrhetic shellfish poison was not detected. No radioactivity was detected. These results suggest that oysters intended for raw consumption or use in seafood products should be subjected to chemical and biological controls.

• Journal of the East Asian Society of Dietary Life
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• v.24 no.4
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• pp.481-487
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• 2014

This study examined microbiological contamination of street foods(kimbab, fish cake, Korean sausage) by microbiological analysis. A collection of 360 samples of street foods was obtained seasonally in four major cities(Seoul, Daejeon, Busan, Gwangju) in Korea. Aerobic mesophilic counts ranged between 1.0 and 9.9 log CFU/g, with the highest count recorded from Kimbab. Counts of psychrotrophic microorganisms were as high as those of mesophilic microorganisms. Total coliform populations between <1.0 and 7.5 log CFU/g were found in 53.6% of samples. Escherichia coli 4.4%, Staphylococcus aureus 7.8% and Clostridium perfringens 3.3%. Salmonella spp. and Listeria monocytogenes were not detected in any of the samples. Kimbab purchased in spring and summer showed higher S. aureus and Cl. perfringens contamination rates. Microbial contamination levels determined in the present study may be used as the primary data to execute microbial risk assessment of street foods.

• The Korean Journal of Food And Nutrition
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• v.20 no.3
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• pp.295-303
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• 2007

As a result of life-style changes, consumer's concerns of food have shifted from calories and nutrition to health and convenience. Fresh-cut products are one such new direction for fruit and vegetable consumption. In this study, the vitamin C, mineral, and pesticide contents of various fresh-cut products were analyzed. According to sensory evaluations, the key reason for a lower than expected overall acceptability of many fresh-cut products is that they are likely to have browning and can easily lose their freshness. Also, the sensory evaluation showed that shriveling, the degree of browning, softening around the cut edge, and off-flavors were the primary factors affecting the quality of fresh-cut products. As a nutritional factor of quality, vitamin C content was not practical with regard to fresh-cut lettuce because the level was very low. For product safety, residual pesticides were detected in the fresh-cut products, but the results showed that all items were under permitted levels and considered safe. In evaluation of the microbial levels of the fresh-cut market products, the levels of viable cells, mold, yeast, coliform bacteria, and enterobacteriaceae were not significantly different based on the summer and winter seasons. The levels of S. aureus and Listeria spp. in the products were higher during the summer season than the winter.