• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1149-1155
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• 2020

Silage is one of the main feed components of ruminants around the world and can make up about 50-80% of the rations of dairy cows during the winter. The aim of this study was to evaluate the usability of oregano (Origanum vulgare L.) and thyme (Thymus vulgaris L.) aqueous and ethanol extracts to improve the hygienic quality of perennial ryegrass, red clover and blue alfalfa silage samples and estimate their effect on mycotoxins concentrations. Under laboratory conditions, 63 silage samples (21 perennial ryegrass, 21 blue alfalfa, 21 red clover) were fermented with inserted aqueous and ethanol extracts of oregano and thyme and two commercial inoculants with mesophilic lactic acid bacteria. After 96 days of fermentation, in silage samples were established fermentation parameters, microbiological status and mycotoxins concentrations. It was determined that the best results for achieving hygienic quality of perennial ryegrass and red clover silage samples was by insertion of aqueous and ethanol extracts of oregano and thyme. In blue alfalfa samples, the best results of silage hygienic indicators were determined by inserting aqueous and ethanol extracts of oregano. Aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZEA) and T-2 toxin concentrations in perennial ryegrass, red clover and blue alfalfa silage samples were best reduced by inserting aqueous and ethanol extracts of oregano and thyme. The present study shows that these extracts can be used to improve silage hygienic quality, reduce mycotoxins concentrations and thus ensure the wellness of cattle.

• Journal of Food Hygiene and Safety
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• v.33 no.2
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• pp.94-101
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• 2018

Although Kimchi has health benefits, food poisoning associated with consumption of Kimchi has been frequently reported. Accordingly, microbiological properties of Kimchi (100 samples) and washing effects on microbial reduction against its ingredients (200 samples) were examined. Total aerobic bacteria, coliforms, Escherichia coli, Bacillus cereus, and Clostridium perfringens were quantified. In addition, B. cereus, Salmonella spp., Enterohemorrhagic E. coli, C. perfringens, Campylobacter jejuni/coli, Staphylococcus aureus, Vibrio parahaemolyticus, Listeria monocytogenes, and Yersinia enterocolitica were analysed qualitatively. Total aerobic bacteria count was approximately 1.4-9.0 log CFU/g, which were highest in ginger (8.8 log CFU/g), and Chonggak Kimchi (9.0 log CFU/g). The range of coliform counts detected in all raw materials was 0.5-7.3 log CFU/g and ginger showed the greatest number 7.3 log CFU/g among others. Contamination was decreased to 0.2-3.2, 0.3-2.7, and 1.0-3.9 log CFU/g for total aerobic bacteria, coliforms, and B. cereus, respectively, after washing. Minimising microbial contamination in Kimchi ingredients is necessary to ensure the safety of Kimchi. These results indicate that washing is a useful method to reduce bacterial contamination in Kimchi.

• Journal of Microbiology and Biotechnology
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• v.31 no.1
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• pp.70-78
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• 2021

Identifying the extracellular metabolites of microorganisms in fresh vegetables is industrially useful for assessing the quality of processed foods. Pectobacterium carotovorum subsp. carotovorum (PCC) is a plant pathogenic bacterium that causes soft rot disease in cabbages. This microbial species in plant tissues can emit specific volatile molecules with odors that are characteristic of the host cell tissues and PCC species. In this study, we used headspace solid-phase microextraction followed by gas chromatography coupled with mass spectrometry (HS-SPME-GC-MS) to identify volatile compounds (VCs) in PCC-inoculated cabbage at different storage temperatures. HS-SPME-GC-MS allowed for recognition of extracellular metabolites in PCC-infected cabbages by identifying specific volatile metabolic markers. We identified 4-ethyl-5-methylthiazole and 3-butenyl isothiocyanate as markers of fresh cabbages, whereas 2,3-butanediol and ethyl acetate were identified as markers of soft rot in PCC-infected cabbages. These analytical results demonstrate a suitable approach for establishing non-destructive plant pathogen-diagnosis techniques as alternatives to standard methods, within the framework of developing rapid and efficient analytical techniques for monitoring plant-borne bacterial pathogens. Moreover, our techniques could have promising applications in managing the freshness and quality control of cabbages.

• Journal of Microbiology and Biotechnology
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• v.34 no.3
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• pp.622-633
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• 2024

For quality standardization, the application of functional lactic acid bacteria (LAB) as starter cultures for food fermentation is a well-known method in the fermented food industry. This study assessed the effect of adding a non-thermally microbial inactivated starter culture to kimchi, a traditional Korean food, in standardizing its quality. In this study, pretreatment based on sterilization processes, namely, slightly acidic electrolyzed water (SAEW) disinfection and ultraviolet C light-emitting diode (UVC-LED) of raw and subsidiary kimchi materials were used to reduce the initial microorganisms in them, thereby increasing the efficiency and value of the kimchi LAB starter during fermentation. Pretreatment sterilization effectively suppressed microorganisms that threatened the sanitary value and quality of kimchi. In addition, pretreatment based on sterilization effectively reduced the number of initial microbial colonies in kimchi, creating an environment in which kimchi LAB starters could settle or dominate, compared to non-sterilized kimchi. These differences in the initial microbial composition following the sterilization process and the addition of kimchi LAB starters led to differences in the metabolites that positively affect the taste and flavor of kimchi. The combined processing technology used in our study, that is, pre-sterilization and LAB addition, may be a powerful approach for kimchi quality standardization.

• Journal of Microbiology and Biotechnology
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• v.29 no.10
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• pp.1580-1590
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• 2019

Capsaicinoids in red pepper powder are known to show anti-bacterial effects; however, their effects during kimchi fermentation are not known. This study aimed to investigate the effects of various concentrations of capsaicinoids on kimchi fermentation. Five sets of kimchi samples were prepared using 0 mg/kg (control), $98.34{\pm}5.34mg/kg$ (mild), $243.47{\pm}3.71mg/kg$ (medium), $428.63{\pm}30.78mg/kg$ (hot), and $1,320.49{\pm}28.27mg/kg$ (extreme) capsaicinoid. The characteristics of each kimchi sample, including pH, acidity, organic acid, sugars, sugar alcohol, capsaicinoid content, and microbial community were periodically investigated during fermentation. Kimchi with red pepper powder shows significantly higher acidity than control kimchi, whereas pH values were the same. Organic acid in kimchi with red pepper powder was higher than in control kimchi, probably caused by higher lactic acid bacteria (LAB) counts in kimchi samples with red pepper powder. Our results show that addition of red pepper powder decreased Leuconostoc spp. counts in the bacterial community. In particular, Lactobacillus sakei and Leuconostoc gelidum counts increased and decreased, respectively, with increasing capsaicinoid content of red pepper powder added to kimchi. Overall, the results of this study indicate that physicochemical properties and LAB such as L. sakei and L. gelidum are influenced by capsaicinoid content. However, further studies are necessary to investigate the effects of the percentage of red pepper powder in kimchi on fermentation to provide practical guidelines for producing standardized kimchi.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.2019-2027
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• 2017

Recently, cabbage kimchi has occasionally been associated with the foodborne diseases of enteric viruses such as human norovirus (HuNoV). This study aimed to evaluate the correlation between microbial/physicochemical properties and persistence of HuNoV in experimentally contaminated cabbage kimchi fermented and stored at $4^{\circ}C$ or $10^{\circ}C$ for 28 days. Changes in organic acid content, lactic acid bacteria (LAB), acidity, pH, and salinity were analyzed. The recovery of structurally intact HuNoV was examined for up to 28 days post-inoculation, using a NoV GII.4 monoclonal antibody-conjugated immuno-magnetic separation method combined with quantitative real-time reverse transcription polymerase chain reaction. On day 0, LAB loads were $4.70log_{10}$ colony forming units/g and HuNoV GII.4 titers were $2.57log_{10}\;genomic\;copies/{\mu}l$, at both temperatures. After 28 days, intact HuNoV titers decreased to 1.58 ($4^{\circ}C$) and $1.04(10^{\circ}C)log_{10}\;genomic\;copies/{\mu}l$, whereas the LAB density increased. This correlated with a gradual increase in lactic acid and acetic acid at both temperatures. Our findings support a statistical correlation between changes in physicochemical properties and the recovery of structurally intact HuNoV GII.4. Moreover, we determined that the production of organic acid and low pH could affect HuNoV GII.4 titers in cabbage kimchi during fermentation. However, HuNoV GII.4 was not completely eliminated by microbial/physicochemical factors during fermentation, although HuNoV GII.4 was reduced. Based on this, we speculate that the persistence of HuNoV GII.4 may be affected by the continually changing conditions during kimchi fermentation.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.151-161
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• 1994

Gamma irradiation was applied to red ginseng for improving its quality. Irradiation at 5~7 kGy was effective for sterilizing all contaminated microorganisms of red ginseng. At the dose levels, no significant shanges in physicochemical properties (color, saponin, lipid rancidity and fatty acids etc.) were observed even after 6 months storage. Gamma irradiation was also effective for the improving hygienic quality of packed red ginseng with high moisture content (up to 20%), without any quality deterioration.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.123-129
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• 1990

• Korean Journal of Community Nutrition
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• v.15 no.6
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• pp.806-819
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• 2010

We investigated the foodservice sanitation status of the childcare centers in Chungnam Asan area to provide the information for sanitation guidelines and checklist in various operation types of childcare centers. Self-completed questionnaires were collected from the directors of 95 centers: national-public 9 (9.5%), corporation 10 (10.5%), private 52 (54.7%), and home care 24 (25.3%) types. The analyzed results are shown in foundation type; the investigated items are about critical hygienic problems and safety recognition level, presence of sanitation guideline, demand of dietian's employment and the role, hygienic management and education level, and the present and future of sanitary facility and equipment. From this study we found that home care center, which had low capacity, was comparatively poor at sanitation status, the use of hygienic standard and guideline, and safety recognition level. In our opinion, the use and application of same sanitation standard to any type and size of center is not appropriate and rational. The reestablishment of the sanitation guideline and checklist considering the conditions of various operation types would be necessary. Also periodic hygienic education by hygenic professionals, continuous parents' attention and cooperation of related government organizations are needed for improvement of foodservice sanitation status of childcare centers.

• Food Science and Preservation
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• v.31 no.1
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• pp.24-32
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• 2024

This study evaluates the microbial safety of ginseng sprouts packaged in moss and a modified atmosphere (MA) film within Styrofoam boxes. Ginseng sprout samples were stored at 4℃ for seven days, and the total fungi and aerobic bacteria counts, relative humidity, and moisture content were measured at 0, 1, 3, 5, and 7 days. During the storage period, both packaging treatments caused an increase in the total fungi and aerobic bacteria counts. However, by the seventh day, the ginseng sprouts packaged in the MA film demonstrated significantly lower counts of total fungi (3.03 log CFU/g) and aerobic bacteria (7.32 log CFU/g) than those in moss (3.66 and 7.63 log CFU/g, respectively). Moss packaging alone resulted in the total fungi count reaching up to 3.36 log CFU/g, with the aerobic bacteria count consistently exceeding 7 log CFU/g, highlighting the importance of hygienic management. Moreover, no significant differences were observed in the moisture content and relative humidity between the MA-film- and moss-packaged groups throughout storage. These findings indicate that the functional MA film is a more hygienic packaging solution for ginseng sprouts than moss.