• Journal of Food Hygiene and Safety
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• v.2 no.1
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• pp.29-34
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• 1987

ABSTRACT$.$ Ethylene oxide (E.O) fumigation and gamma irradiation were applied to compar$.$ ative researches on the microbiological, physical and cooking quality of dried oak mushroom stored at $25^{\circ}C$ and different relative humidities. The equivalent moisture contents of dried oak mushroom for the limiting growth of general molds and xerophilic mold at $25^{\circ}C$ were shown to be 17% and 27% respectively. Total aerobic bacteria, molds and coliforms were sterilized at 5 kGy irradiation but E.O. fumigation was proved insufficient to eliminate the molds. The hydration rate of dried oak mushroom increased according to the increase of irradiation dose and soaking temperatures. and an irradiation by 5 kGy could shorten the hydration time of the sample as compared to E.O. treatment and control group. Sensory evaluation for the irradiated cooked sample was not significantly different in flavour but the texture of the gamma irradiated sample was significantly better(p < 0.01) than that of E. O. fumigated sample.sample.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.955-961
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• 2020

Lactic acid bacteria (LAB) have caused many microbiological incidents in the brewing industry, resulting in severe economic loss. Meanwhile, traditional culturing method for detecting LAB are time-consuming for brewers. The present review introduces LAB as spoilage microbes in daily life, with focus on LAB in the brewing industry, targeting at the spoilage mechanism of LAB in brewing industry including the special metabolisms, the exist of the viable but nonculturable (VBNC) state and the hop resistance. At the same time, this review compares the traditional and novel rapid detection methods for these microorganisms which may provide innovative control and detection strategies for preventing alcoholic beverage spoilage, such as improvement of microbiological quality control using advanced culture media or different isothermal amplification methods.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.324-329
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• 2013

This study investigated and evaluated contamination levels of bacteria on tomatoes at farms stage to evaluate potential hazards associated with fresh tomatoes. A total of 170 samples, 90 samples from 5 sampling sites from 18 farms and 80 samples from 1 sampling site from 4 farms every month for four months, were analyzed to enumerate aerobic bacterial counts, coliforms, E. coli, Bacillus cereus, Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes. Aerobic bacterial counts ranged from 0.48 to 6.15 Log CFU/g, with the lowest and the highest bacterial cell counts recorded for A site and E site, respectively. Thirty five percent of the samples from the E site contained more than 2 Log CFU/g. Six samples (6.6%) of 90 samples contained B. cereus less than 1 Log CFU/g. In addition, the contamination level of indicator bacteria and B. cereus in tomatoes were higher on March than on April, May and June (P < 0.05). S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in the tomato samples. The microbial contamination levels of tomatoes determined in this study may be used as the data for microbiological risk assessment.

• Journal of the FoodService Safety
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• v.2 no.2
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• pp.84-90
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• 2021

This study was performed to assess the microbiological quality and safety of microgreen sampled from harvesting farms and food processing plant in Korea. The samples were analyzed for total viable counts, coliforms, Enterobacteriaceae, Escherichia coli, Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Bacillus cereus, and Staphylococcus aureus. Total viable counts were highly contaminated in samples collected from farms (7.7~8.2 log CFU/g) and the final products (5.8~7.8 log CFU/g), respectively. B. cereus was detected less than 100 CFU/g, which was satisfied with Korean standards (<1,000 CFU/g) of fresh-cut produce. A predictive model was developed for the changes of total viable counts in microgreens during storage at 5~35℃. The predictive models were developed using the Baranyi model for the primary model and the square root model for the secondary model. The results obtained in this study can be useful to develop the safety management options along the food chain, including fresh-cut produce storage and distribution.

• Food Science of Animal Resources
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• v.38 no.4
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• pp.664-678
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• 2018

This study was carried out to establish shelf life for pork cutlet of ground meat and pork lard by using various quality indicators and to understand how quality changes in these products are accelerated by temperature. The samples were selected and purchased from markets in Korea, and the chosen quality indicators were total aerobic counts and coliform group in microbiological analyses, thiobarbituric acid reactive substances assay, volatile basic nitrogen, pH, acid value, and peroxide value in physical chemical analyses, and sensory evaluation. The pork cutlet samples were stored at $-18^{\circ}C$, $-6^{\circ}C$, and $-1^{\circ}C$, whereas pork lard samples were stored at $10^{\circ}C$, $25^{\circ}C$, $35^{\circ}C$, and $45^{\circ}C$. These temperature conditions were set to real distribution conditions. The samples were then analyzed using various models including of reaction orders, arrhenius equation, and $Q_{10}$ value. The quality limits for each sample were calculated, and shelf life was estimated. The results of this experiment highlighted the importance of temperature control during the distribution process of these products and revealed that temperature is a useful parameter for the establishment of a basic database for shelf life.

• Journal of Food Hygiene and Safety
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• v.15 no.3
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• pp.256-261
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• 2000

Effect of gamma irradiation on quality properties of half·cooked noodle was studied. The noodle were treated with lactic acid(0.1%, w/w), heat(10 min in boiling water) or their combination after cooking for 3 min, and irradiated at 0, 5 and 10 kGy. The noodle were stored at 25。C for 5 weeks and microbial population, Aw, pH, and texture profiles were examined. Fungi were completely eliminated by gamma-irradiation with 5 or 10 kGy does. Number of aerobic bacteria were also decreased by 2 and 4 log cycles with dose of 5 and 10 kGy, respectively. The D10 values of aerobic bacteria were 2.34∼2.95 kGy. Growth of the aerobic bacteria that survived even at 10 kGy of irradiation were significantly inhibited during storage. Acidification of half-cooked noodle was suppressed by gamma irradiation but A${_w}$ were not affected. Stickiness was decreased at the beginning of storage by gamma irradiation but was restored after 3 weeks. The results indicated that the gamma irradiation would be useful to improve quality and storage stability of half-cooked noodle.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.205-213
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• 2013

The objective of this study was to evaluate the quality characteristics of sun-dried Hanwoo beef jerky added with Salicornia herbacea (SH). Sliced Hanwoo beef shank were marinated and sun-dried at $28-30^{\circ}C$, relative humidity (RH) 30-35% for 3.5 h. The physicochemical and microbiological traits of the Hanwoo beef jerky were analyzed during the aerobically packaged storage at $25^{\circ}C$. The water activities of beef jerky with 0.5% and 1.0% SH were lower than those of the control at 0 d (p<0.05). The pH values of beef jerky with SH were significantly higher than those of the control (p<0.05). The beef jerky with SH and ascorbic acid showed significantly lower TBARS values than the control (p<0.05). The beef jerky with SH showed a significantly lower redness ($a^*$) than the control (p<0.05). Total plate count (TPC) of beef jerky with 1.0% SH was significantly lower than that of the control during the storage of 20 d (p<0.05). Yeast/mold was detected in the control and beef jerky with SH after storage periods of 10 and 20 d, but was not detected in jerky with ascorbic acid. With regard to the sensory properties, beef jerky with SH showed significantly greater flavor scores than the others (p<0.05). The result shows that SH powder can be used to increase the sensory quality and microbial safety of beef jerky.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.189-195
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• 2016

Objectives: To ensure the microbiological safety of groundwater, it was confirmed whether waterborne pathogenic bacteria in groundwater samples tested positive for total coliforms in the Chungcheongnam-do Province region. Methods: Total colony counts, total coliforms and fecal coliforms were tested according to the process mandated by the drinking water quality testing standards of Korea. DNA was extracted from the samples, tested positive for total coliforms, and then subjected to real-time PCR to detect waterborne pathogenic bacteria. Results: A total of 115 samples were inadequate for drinking water. Thirty-one cases (27%) showed positive for fecal coliforms and nine cases (7.8%) showed total colony counts exceeding drinking water standards. Twenty-seven cases (23.5%) showed three items (total colony counts, total coliforms and fecal coliforms). Using the real-time PCR method, waterborne pathogens were detected in 57 cases (49.6%) in 115 samples. Seventy-eight cases of waterborne pathogenic bacteria were detected (including duplications): 27 cases of pathogenic E. coli (EPEC (19), ETEC (5), EHEC (1), EAEC (1) and EIEC (1)); 45 of Bacillus cereus; two of Yersinia spp.; two of Salmonella spp.; one of Staphylococcus aureus; one of Clostridium perfringens. Conclusion: The real-time PCR method can offer rapid and accurate detection of waterborne pathogenic bacteria. Therefore, this assay could be an alternative to conventional culture methods and can further ensure the microbiological safety of groundwater.

• Journal of Food Hygiene and Safety
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• v.2 no.3
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• pp.97-102
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• 1987

The effects of gamma irradiation on microbiological and physicochemical qualities in raw ingredients (thirteen kinds of cereal grain and their by-product) of mixed feeds were investigated. The total aerobic bacteria counts in the samples were $10^2\;to\;10^6/g$. They were sterlllzed to a undetectable level by 5 to 7 kGy irradiation. Coliforms were contaminated in high levels in all sample, ranging from $10^2\;to\;10^6/g$. They were radiation-llensitive and completely eliminated by irradiation with 3 to 5 kGy. Total fungi, ranging from $10^2\;to\;10^4/g$, mainly osmophiles were identified as Aspergillus and Penicillium. They were eliminated below identification limit by 5 to 7 kGy irradiation. Seven kinds of species, including Aspergillus IkrlJUB. were identified as a potential mycotoxin producers. Physicochemical qualities, such as total amino acid content, total sugar content. TBA value and color difference showed that an optimum dose of irradiation was less detrimental than ethylene oxide fumigation.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.57-62
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• 2007

Microbiological, pH, and sensory evaluations on pork tender-loins treated with potassium sorbate (PS) during storage at $4^{\circ}C$ were assessed. Treatments of 0.5-2.0% PS for 10 min effectively (P < 0.05) inhibited the growth of aerobic plate counts (APC) and gram-negative bacterial counts (GNC) compared to those of controls for 9 days at $4^{\circ}C$, respectively. Results of this investigation demonstrate that antimicrobial activity on APC and GNC in all treatments enhanced by increasing concentrations of PS during storage at $4^{\circ}C$. pH values of pork tender-loins treated with PS gradually increased by storage of 6 days at $4^{\circ}C$. Sensory data showed that 0.5-1.0% PS treatments were quite close in odor and appearance compared to fresh controls. Results indicated that pork tender-loins treated with 1.0% PS for 10 min could extend shelf-life to 9 days during refrigerated storage at $4^{\circ}C$ without adversely affecting sensory quality.