• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.372-380
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• 2020

In this study, the sterilization ability of S. aureus and P. aeruginosa was evaluated using a plasma generator with a flexible electrode structure. Both strains were prepared at a concentration of 1.5×106 CFU/mL and inoculated and spread evenly on two medium plates. The medium were kept at a distance of 3 cm and 9 cm from the plasma generator and were plasma discharged from 30 sec to 10 minutes. The growth of colonies on the media, were subsequently compared with the control group. The mean colonies of S. aureus formed at a 3 cm distance were 9.2×102 (log value 2.96) CFU/mL for the 5 min discharge period and 8.0×10 (1.90) CFU/mL for the 10 min discharge period. When the medium was exposed for 5 min and 10 min at a 9 cm distance, the mean colonies of S. aureus formed were 2.16×103 (3.33) and 2.4×102 (2.38) CFU/mL, respectively. The medium containing P. aeruginosa kept at a 3 cm distance and exposed to 3, 5, 10-minute discharge, did not form any colonies. When kept at a 9 cm distance for 3 minutes, 6.0×102 (2.78) CFU/mL mean colonies were formed but no colonies were formed at exposure periods of 5 and 10 minutes. This enhanced sterilization effect was confirmed in experiments of S. aureus and P. aeruginosa using TiO2.

• Food Science and Preservation
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• v.16 no.4
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• pp.567-572
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• 2009

We evaluated the microbiological quality of a facility in which freshly cut onions were prepared. The total plate counts on walls, equipment, and raw materials were ND (not detected) to $10^1$ CFU/100 $cm^2$, $10^0{\sim}10^3$ CFU/100 $cm^2$, and $10^3{\sim}10^4$ CFU/g, respectively. No coliforms were detected on walls however, coliforms were detected at concentrations of ND to $10^3$ CFU/100 $cm^2$ and $10^3{\sim}10^4$ CFU/g on equipment and raw materials, respectively. The total plate counts for falling and floating bacteria in the processing plant were ND to $10^0$CFU/plate and $10^1{\sim}10^2$ $CFU/m^3$, respectively. Pathogenic microorganisms such as Escherichia coli, Salmonella spp, Staphylococcus aureus, and Listeria monocytogenes were not detected on walls, equipment, or raw materials. Overall, the results of the study indicate that hygiene control at the fresh-cut processing plant should be improved.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.243-248
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• 2011

The prevalence and distribution of hazardous microorganisms were investigated from the major perilla cultivation area at Milyang, Gyeongnam province, Korea. Aerobic plate count (APC) and coliform count of perilla leaves were 4.82 log CFU/g and 3.85 log CFU/g, respectively. E. coli, S. aureus and B. cereus were detected in 3.0% (4/114), 7.9% (9/114) and 46.5% (53/114) of examined perilla leaves. However, E. coli O157:H7, Salmonella spp, and L. monocytogenes were not detected. The distribution of hazardous microorganisms in perilla leaf cultivation environment were compared and the concentration of APC and coliform counts were more than 3.0 log CFU/(mL, g, $100cm^2$, hand) from most of the samples. S. aureus were detected from irrigation water, packing table, packing vinyl, hand, and clothes. Also, B. cereus was frequently detected from the examined samples. Especially, packing table and collection container were contaminated with maximum 5.5 log $CFU/100cm^2$ of B. cereus. Good Agricultural Practice (GAP) system should be introduced to farms to enhance the safety of perilla leaves.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.403-410
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• 2013

This study was performed to evaluate the microbiological contamination level of raw beef from retail markets in Seoul, Korea. The sampling and laboratory test were performed according to the procedure of "Standard for processing and ingredients specification of livestock product" and "Korean food code". Enterotoxin of Staphylococcus aureus isolates were detected using VIDAS$^{(R)}$ and PCR-based methods. Listeria monocytogenes serotyping and genotyping were carried out using Listeria antisera and L. monocytogenes Fingerprinting kit, respectively. A total of 48 samples were collected from 16 retail markets (butcher's shop: 5, department store: 6, supermarket: 5) in 2011. The level of total bacteria counts in the butcher's shop, department store and supermarket were $4.4{\times}10^3$ CFU/g, $3.9{\times}10^5$ CFU/g and $1.0{\times}10^4$ CFU/g, respectively. The concentrations of Escherichia coli of these three retail markets were $6.4{\times}10$ CFU/g, 7.6 CFU/g and $2.0{\times}10$ CFU/g, respectively. Salmonella species was not detected on all samples. However, S. aureus was isolated in the 3 samples (6.25%) from each type of three retail markets. L. monocytogenes was isolated in the 4 samples (8.3%) from department stores. The level of contamination of these foodborne bacteria was less than 100 CFU/g. The enterotoxin-encoding genes of S. aureus isolates were sea, seh, sei and sep gene. The gene similarity of L. monocytogenes isolated from two retail markets by Rep-PCR showed 57.8-98.1% and 68.1-98.1%, respectively. These results suggest that the HACCP guideline for environmental control in slaughterhouse and retail markets should be provided to prevent cross contamination and manage foodborne pathogens such as L. monocytogenes and S. aureus.

• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.295-300
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• 2012

The purpose of this study was to analyze microbiological hazards for plants, cultivation environments and personal hygiene of perilla leaf farms at the harvesting stage. Samples were collected from three perilla leaf farms(A, B, C) located in Gyeongnam, Korea and tested for sanitary indications, fungi and pathogenic bacteria(Escherichia coli O157:H7, Listeria monocytogens, Salmonella spp., Staphylococcus aureus and Bacillus cereus). As a result, total bacteria and coliform in perilla leaf were detected at the levels of 4.4~5.2 and 3.4~4.3 log CFU/g, respectively, but E. coli was not detected in all samples. Among the pathogenic bacteria, B. cereus(perilla leaf: 2.0~2.4 log CFU/g, stem: 1.4~2.1 log CFU/g, water: 0.7 log CFU/ml, soil: 4.2~5.0 log CFU/g, hands: 3.0 log CFU/ hand, gloves: 2.1~2.4 log CFU/100 $cm^2$, glothes: 1.5~2.8 log CFU/100 $cm^2$) and S. aureus(3.4 log CFU/hand) were detected in all samples and worker's hand from farm A, respectively. However, other pathogenic bacteria were not detected. This study demonstrates that perilla leaf at the harvesting stage was significantly contaminated with microbial hazards.

• Journal of the Korean Dietetic Association
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• v.12 no.2
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• pp.172-184
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• 2006

This study was aimed to provide safety management guidance by evaluating the microbial quality of cooked dried-seafoods in school foodservice operations. Nineteen seafood items were collected from six elementary schools, those were dried-anchovy, dried-seaweed and dried-fish, which were classified as cooking process. The temperatures at receiving and after cooking were measured and the analyses of cooking processes and microbial quality were performed. The temperatures of all foods after cooking were higher than the temperature limit of $74\^circC$. The number of total aerobic bacteria and S. aureus in dried-anchovy over the limit of $10^5$ and even the level of S. aureus was found to be unsatisfactory. The count of total aerobic bacteria was 2.1x$10^8$ CFU/g and the number of total aerobic bacteria after cooking was over the limit in one school. The level of E. coli (3.1x$10^3$ CFU/g) was over the limit at one school and the number of S. aureus (1.2×$10^4$ CFU/g) was considered as unacceptable. Dried- tangle and green laver were contaminated with total aerobic bacteria showing the over the limit. The numbers of total aerobic bacteria in dried- filefish, pollack and squid were 4.3x$10^6$, 3.4x$10^6$-3.9x$10^7$ and 4.6x$10^5$-4.1x$10^7$ CFU/g, respectively, which were in acceptable or unsatisfactory level. The E. coli in dried- filefish and pollack were over the limit. The total aerobic bacteria levels, 4.6x$10^5$-1.5x$10^6$ CFU/g in dried-pollack and 8.0x$10^5$-2.2x$10^7$ CFU/g in dried-squid, were over the limit after cooking except dried-filefish. The E. coli levels, 4.3x$10^3$ CFU/g in dried-filefish and 2.5x$10^2$ CFU/g in dried-pollack, were over the limit of $10^2$ CFU/g. The numbers of Enterobacteriaceae were either acceptable (3.3x$10^3$ CFU/g) or unsatisfactory (1.6x$10^4$ CFU/g) level in dried-pollack. S. aureus was unsatisfactory level (6.5x$10^4$ CFU/g) in dried-filefish while unacceptable in dried-pollack both before and after cooking. Unacceptable levels of S. aureus, 2.4x$10^4$ and 1.3x$10^5$ CFU/g were found from two schools, respectively. These results suggest that the contamination of raw materials and the seasonings added after cooking should be controlled to manage the microbial safety of cooked dried-seafoods.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.203-208
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• 2011

This study was to evaluate the efficacy of sanitizer concentrations and treatment time against two major toad-borne pathogenic microorganisms such as Escherichia coli and Staphylococcus aureus on a stainless steel surface. As a result, stainless steel, treated with 100 ppm of chlorine showed reduction of E. coli(1.56, 1.49, 1.95 log cfu/25 $cm^2$) and S. aureus(0.49, 0.88, 1.27 log cfu/25 $cm^2$) after 0, 5 and 10 min, but none was not detected in treatment with 200 ppm. The population of E. coli(0.73, 0.90, 1.55 log cfu/25 $cm^2$) and S. aureus(0.37, 1.00, 1.45 log cfu/25 $cm^2$) reduced in 35.5% ethanol treated group, but none was not detected in treatment with 70%. The population was reduced E coli(0.28, 0.64, 1.07 cfu/25 $cm^2$) and S. aureus(0.53, 0.87, 0.99 log cfu/25 $cm^2$) by treatment with 45.5 ppm of hydrogen peroxide, but none was not detected in treatment with 91 ppm. Quarternary ammonium compound with 100 ppm was reduced E. coli(0.82, 1.62, 1.71 log cfu/25 $cm^2$) and S. aureus(0.46, 0.93, 1.38 log cfu/25 $cm^2$), but none was not detected in treatment with 200 ppm. Predictive models of sterilization for all 4 disinfectants were suitable to use with $r^2$ value of higher than 0.94. These models may be of use to food services and manufacture of safe products by controlling E. coli and S. aureus without the need for further detection of the organisms.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.244-250
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• 2008

To evaluate bacteriological water quality, samples were taken from drinking water dispensers placed at S company (S-C) and U highschool (U-H) in Ulsan. The medians of heterotrophic plate counts (HPCs) were 53 CFU/ml for the 74 water samples of S-C and 80 CFU/ml for the 36 cold water samples of U-H, and 38% of the S-C and 42% of the U-H samples showed HPC bacterial concentrations higher than 100 CFU/ml. Coliform bacteria were detected from one sample of S-C. To determine the major source of bacterial contamination, water samples were taken daily for $6\sim8$ days from the bottled water containers as well as the faucets of an experimental water dispenser. While the average HPCs in the bottled water containers were 33 CFU/ml for the first and 132 CFU/ml for the 2nd analysis, the HPC concentration in the cold water samples was 1,022 CFU/ml for the 2nd analysis. These results suggest that the majority of bacteria detected in the cold water samples were originated from the biofilms on the surface of water passages within the water dispensers. There was no significant increase in HPC bacterial concentrations within the bottled water container after installation on the water dispenser. We could isolate and tentatively identify 3 genera 6 species of Gram-positive and 7 genera 7 species of Gram-negative bacteria from the plate count agar plates of U-H samples. Among the isolates, 72% were observed as Gram-positive, and Micrococcus spp. was the most abundant with 54% of the total, followed by Sphingomonas paucimobilis with 16%. It appears that most of the HPC bacteria detected in water dispensers originate from indoor airborne bacteria, which may play important roles in the formation of biofilms on the surface of water passages within the water dispensers.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.235-240
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• 2022

In this study, the delivery conditions and microbial contamination in Mille-feuille Nabe and fresh spring roll meal kits purchased online were assessed. The average surface temperature on the product arrival was 14.4℃. The average number of total aerobic bacteria and coliforms in Mille-feuille Nabe was 3.27 log CFU/g and 1.27 log CFU/g, respectively, in meat, and 6.66 log CFU/g and 2.94 log CFU/g, respectively, in vegetables. The average number of total aerobic bacteria and coliforms in fresh spring rolls was 3.82 log CFU/g and 1.93 log CFU/g in meat, and 5.62 log CFU/g and 3.31 log CFU/g in vegetables, respectively. Escherichia coli was detected in bok choy and perilla leaves, with an average of 0.86 log CFU/g. Salmonella spp. and E. coli O157:H7 were not detected in any of the samples; however, Listeria monocytogenes was detected in all three beef samples. Therefore, before consuming meal kits, sufficient washing and heating are recommended to prevent occurrences of food poisoning.

• Journal of Genetic Medicine
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• v.7 no.2
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• pp.138-144
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• 2010

Purpose: Endothelial progenitor cells (EPCs), which mediates neovascularization of uterine endometrium may be involved in the neovascularization in the utero-placental circulation. Low numbers of endothelial progenitor colony-forming unit (CFU) in culture are predictive biomarker of vascular disease. The aim of the present study was to evaluate whether the number of CFU in preeclampsia differed from that in normal pregnancy. Materials and Methods: Women with singleton normal (n=26) or preeclamptic (n=20) pregnancies were studied during the third trimester. The number of EPCs was quantified by CFU methodology. Plasma levels of angiogenic factors, vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase-1 (sFlt-1), and placental growth factor (PlGF) were determined by enzyme-linked immunoassay. Results: CFU numbers were significantly decreased in the preeclamptic patients compared with the controls (median, 3; range 1-12 vs. 31; 3-81 CFU/well, P<0.001). A majority of the cells comprising individual colonies were positive for endothelial characteristics (Ulex europaeus lectin staining and acetylated low-density lipoprotein uptake). Plasma levels of the sFlt-1 were highly elevated (P<0.001) in patient with preeclampsia compared to controls, whereas PlGF were highly reduced (P=0.004), but these factors did not associate with CFU numbers. Conclusion: Our results suggest that reduced numbers of CFU obtained from maternal peripheral blood may contribute to the development of preeclampsia.