• Journal of the Korean Dietetic Association
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• v.19 no.3
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• pp.236-252
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• 2013

The purpose of this study was to assess the microbiological quality of home-delivered meals during production and delivery for children from low-income families. Production flows from a facility in Seoul that provides home-delivered meals were analyzed and the time-temperature of the food was measured. Microbiological assessment was performed for the production environment, personal hygiene, and food samples at each production and delivery step based on the process approach. It took 2 hours or longer from completion of production to meal delivery. An aerobic colony count (ACC) and coliform were not detected at knives, cutting boards, and dish towels. However, ACC (at pre-preparation, preparation, and packing areas) and coliform (at the preparation area) were detected on the hands and gloves of employees. Air-borne bacterial counts varied according to day and preparation area (ND~6 CFU/plate/15 min). Food temperatures, on the completion of production and meal delivery, fell into temperature danger zones. ACC and coliform counts of raw ingredients did not decrease after pre-preparation (washing and sanitizing) for menus involving food preparation with no cook step. ACC decreased after cooking step for menus of food preparation with cook step, but the ACC of the stir-fried and seasoned dried filefish fillet on the completion of cooking was too numerous to count due to improper heating. The ACC of seasoned young Chinese cabbages (a menu with complex food preparation) increased during delivery (from 2.5 log CFU/ml to 5.0 log CFU/ml). This qualitative assessment of foodborne pathogens revealed that B. cereus was detected in vegetable and meat product menus. These results suggest time-temperature control is necessary during production and delivery and management guidelines during production of home-delivered meals are provided for safe production.

• Journal of Life Science
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• v.22 no.9
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• pp.1194-1200
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• 2012

Lactic acid bacteria are generally recognized as beneficial probiotic organisms. Recent studies revealed that the potential of probiotic strains was essentially dependent on the bacterial-binding and adhesion capabilities to gut epithelial cells and the hydrophobicity of the cell surface. In this study, we screened some indigenous lactic acid bacteria from Kimchi and selected one lactic acid bacterium as a potential probiotic based on its cell surface hydrophobicity. Analysis of the 16S rRNA gene sequences of probiotic isolates indicated that the selected isolate (BCNU 9070 strain) was a member of Pediococcus pentosaceus. P. pentosaceus BCNU 9070 showed resistance to bile acids and acidic pH. The P. pentosaceus BCNU 9070 strain also inhibited the cell growth of six food-borne pathogens including Listeria monocytogenes and Shigella sonnei. In addition, the P. pentosaceus BCNU 9070 strain expressed bile salt hydrolase activity and showed an ability to assimilate cholesterol in vitro. On the basis of these results, P. pentosaceus BCNU 9070 is considered to have probiotic potential for applications in functional foodstuffs.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.595-598
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• 2000

Aeromonas hydrophila is a pathogen to fish as well as human. It is a food-borne disease, and causes severe mortality in fish, and sometimes severe septicemia in human. In this study, a rapid detection method using latex agglutination has been developed for A. hydrophila. Polyclonal antibodies were raised against membrane and whole cells of three isolates from rainbow trout. Among these, latex particles coated with antibodies raised against whole cells of isolate No. 2 showed the best sensitivity. With latex particles coated with this antibody, we could detect $5{\times}10^4$ CFU of A. hydrophila in 5 min. The cross-reactivity with bacteria constituting the normal intestinal microflora and other pathogens for rainbow trout was insignificant. This latex agglutination assay method produced positive reaction with all clinical isolates of A. hydrophila which were identified by species-specific PCR for 16S rRNA in A. hydrophila.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.503-508
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• 2005

Screening for antilisterial activity was performed in about three thousand isolates of lactic acid bacteria (LAB) from Chinese cabbage kimchi, and finally based on the relatively stronger antilisterial activities eight bacterial strains were selected. The bacteria were further characterized in terms of their tolerance to artificial gastric juice, pH 2.5, bile salts (0.3% oxgall), and to the different NaCl concentrations. Of the isolates, YK005 was especially investigated for its physiological characteristics due to its inhibitory activity against gram-positive Listeria monocytogenes as well as gram-negative Escherichia coli O157:H7, as they have been constantly reported to be resistant against bacteriocins produced by a number of LAB strains. YK005 was found to be rod-shaped, $3.8\;{\mu}m$ long ${\times}\;0.5\;{\mu}m$ wide, non-sporeforming, non-motile, catalase-negative, and produced gas from glucose (heterolactic). Based on the biochemical data obtained by API 50 CHL medium, the isolate was tentatively identified as Lactobacillus brevis. To validate the result obtained by the biochemical identification, rRNA-based PCR experiments using a pair of species-specific primers for L. brevis were conducted and a single band of 1400 bp was observed, which strongly indicated that YK005 belongs to L. brevis. The LAB isolates are potentially exploited as human probiotic organisms and are employed to control some food-borne pathogens like L. monocytogenes.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.437-442
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• 2014

Foodborne illness due to the consumption of contaminated raw strawberries is a continuing food safety concern. This study investigated and evaluated contamination levels of bacteria on strawberries at farms stage to evaluate potential hazards associated with fresh strawberries. A total of 315 samples, 105 samples from 5 sampling sites (A to E) of 21 farms and 210 samples from 1 sampling site of 6 farms, was collected every month for four months and analyzed to enumerate aerobic bacterial counts, Coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study of five pathogens (S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.48 to 6.36 Log CFU/g, with the highest bacterial cell counts recorded for D and E sites. Coliforms were detected in 71 samples (22.5%) with a minimum of 0.48 cfu/g and a maximum of more than 4 Log CFU/g. B. cereus was detected in 98 samples (31.1%) among total samples analyzed. S. aureus was detected in 2 samples with a minimum of 0.48 Log CFU/g and a maximum of 1.38 Log CFU/g. E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not isolated from any of the samples. The microbial contamination levels of strawberries determined in this study may be used as the fundamental data for microbiological risk assessment.

• Journal of Food Hygiene and Safety
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• v.16 no.4
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• pp.264-273
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• 2001

Antimicrobial activities of ave different probiotics (Lactobacillus reuteri, L. acidophillus, L. bulgaricus, L. casei and Bifidobacterium longum) against 8 bacterial pathogens were determined on the Mueller Hinton Agar containing supernatant of probiotics obtained from 3 different growth conditions (MRS without glycerol, MRS with 0.5 M glycerol or 0.25 M glycerol solution). Though antimicrobial activity of L. reuteri in the first two conditions was not better than the others', the activity was significantly higher than that of others in 0.25 M glycerol solution. This prominent effect might be attributable to reuterin, produced by L. reuteri using glycerol. We could detect the presence of reuterin in the supernatant of 0.25 M glycerol solution with 500 MHz Nuclear Magnetic Resonance (NMR). The result of minimum bactericidal concentration (dilution fold) has revealed that reuterin showed pan-bactericidal effects against 8 major food-borne pathogens. To examine any changes of antimicrobial activities of the probiotics, the probiotics were treated with different pH conditions, pepsin or trypsin digestion. Antimicrobial activity of reuterin was not entirely affected by any of these treatments, while the activities of the other probiotics were significantly decreased.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.468-476
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• 2020

We aimed to analyze the microbiological quality of the ready-to-eat (RTE) side dishes collected from traditional markets, supermarkets, and cafeterias in Gyeonggi-do in 2019. A total of 108 samples were analyzed for total aerobic bacterial counts, coliforms and foodborne pathogens depending on place of purchase and cooking methods. Results show that Bacillus cereus was detected in 14 (12.9%) out of 108 samples of side dishes, while no other foodborne pathogens were detected. The mean detected level (range) of total aerobic bacteria depending on place of purchase was 5.8 log CFU/g (3.0 to 8.2 log CFU/g) for traditional markets, 4.3 log CFU/g (2.4 to 7.8 log CFU/g) for supermarkets, and 3.80 log CFU/g (0.0 to 6.8 log CFU/g) for cafeterias, indicating that there was a significant (P<0.05) difference in total aerobic bacterial counts among places of purchase. Among the samples, the highest counts of total aerobic bacteria and coliforms were detected in saengchae (raw vegetables), followed by namul (seasoned herbs, vegetables), bokkeum (stir-fried foods), and jorim (foods cooked in soy sauce). The growth of total aerobic bacteria in seasoned soybean sprouts was inhibited when the sprouts were stored at 4℃ up to 24 h, whereas bacteria rapidly grew at 20 and 35℃ after 3 and 6 h, respectively. These results reveal that storage temperature might play a significant role for the microbiological quality of seasoned soybean sprouts when they are sold in markets. Thus, this study suggests that RTE side dishes should be stored at refrigerated temperature when being sold at markets as well as after purchasing to improve their microbiological quality.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.186-192
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• 2007

This study was conducted to survey the hygienic status of chicken meats on the microbial levels, which were collected from poultry processing plants located in the local provinces in nationwide including the JeJu island (n=15) in 1997. In particular, Salmonella spp., Campylobacter jejuni, and Listeria monocytogenes, which were retarded as one of the most important entero-pathogens relating to food home illness from poultry, were investigated on their isolation frequency including the other pathogens related on the food-borne illness. A total of 115 processed chickens were submitted on the present study. In general, the bacterial contamination frequency showed more or less lower $(10{\sim}100 cells)$ than those of sold on the retail and super markets and department stores because of lacking of cross-contamination incidences, depending on the total cells, Coliforms and Staphylococcal cells count. While, Salmonella species, Campylobacter jejuni, Listeria monocytogenes, and coagulase positive Staphylococcus aureus isolation frequency of chicken meats from slaughter houses were 58.3%, 37.4%, 43.5%, and 30.4%, in order. But the present microbial isolation data were a little lower levels than those of sold on the retail and super markets and famous department stores in Seoul and GyeongGi province at the same period. It seemed that the cross-contamination problems (including the human, environmental and instrumental factors) during the marketing stage (after the last processing procedure; rinsing step) had the major roles on the increasing of the microbial contamination frequency on the chicken meats after the slaughter houses.

• Food Science and Preservation
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• v.16 no.4
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• pp.472-481
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• 2009

Response surface methodology (RSM) is frequently used for optimization studies. In the present work, RSM was used to determine the antimicrobial activitiesof grapefruit seed extract (GFSE) and a lactic acid mixture (LA) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Pseudomonas fluorescens, and Vibrio parahaemolyticus. A central composite design was used to investigate the effects of independent variables on dependent parameters. One set of antimicrobial preparations included mixtures of 1% (w/w) GFSE and 10% (w/w) LA, in which the relative proportions of component antimicrobials varied between 0 and 100%. In further experiments, the relative proportions were between 20% and 100%. Antimicrobial effects against various microorganisms were mathematically encoded for analysis. The codes are given in parentheses after the bacterial names, and were S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$). The optimum antimicrobial activity of the 1% (w/w) GFSE:10% (w/w) LA mixture against each microorganism was obtained by superimposing contour plots ofantimicrobial activities on measures of response obtained under various conditions. The optimum rangesfor maximum antimicrobial activity of a mixture with a ratio of 1:10 (by weight) GFSE and LA were 35.73:64.27 and 56.58:43.42 (v/v), and the optimum mixture ratio was 51.70-100%. Under the tested conditions (a ratio of 1% [w/w] GFSE to 10% [w/w] LA of 40:60, and a concentration of 1% [w/w] GFSE and 10% [w/w] LA, 70% of the highest value tested), and within optimum antimicrobial activity ranges, the antimicrobial activities of the 1% (w/w) GFSE:10% (w/w) LA mixture against S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$) were 24.55, 25.22, 20.20, 22.49, 23.89, and 28.04 mm, respectively. The predicted values at optimum conditions were similar to experimental values.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.599-604
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• 2017

The purpose of this study was to explore methods for efficient management of the quality and safety of simple processed agricultural products in Busan. We tested 258 samples of simple processed agricultural products for distribution of aerobic bacteria and coliforms, and identified food-borne pathogens. The average aerobic bacterial and coliforms counts were 7.1 and 4.1 log CFU/g in simple processed vegetables, 6.8 and 3.5 log CFU/g in dried vegetables, and 6.2 and 2.9 log CFU/g in simple processed fruits. Additionally Staphylococcus aureus, Salmonella spp., Campylobacter jejuni/coli and Listeria monocytogenes were not detected in any samples. However, Bacillus cereus, Clostridium perfringens and E. coli were detected in 41 samples (16.3%), 2 samples (0.8%), and 4 samples (1.6%), respectively. This analysis revealed that none of C. perfringens and E. coli isolates harbored pathogenic toxic genes. However, all of B. cereus isolates carried at least 1 toxin gene.