• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.195-200
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• 2008

Saxifraga stolonifera (Saxifragaceae) is a perennial herbaceous plant growing in Korea, China, Japan and Russia. The aerial part has been used as herbal medicine for treatment of pneumonia, frostbite, inflammation and microbial infection. In this study, fresh juice and methanol extract were prepared from the aerial part of S. stolonifera, and their antimicrobial, antithrombin, and antioxidant activity were evaluated, respectively. The fresh juice showed weak antimicrobial activity against Proteus vulgaris, Escherichia coli O157:H7 and Candida albicans with ignorable DPPH scavenging activity. But, the methanol extract showed strong antioxidant activity ($IC_{50}$ of $37.5{\mu}g/mL$) with minor, broad-range antimicrobial activity. Antithrombin activities were not observed in fresh juice and extract, up to 1.5 mg/mL. Sequential organic solvent fractionation of methanol extract showed that $IC_{50}s$ of ethylacetate and the butanol fraction were 6.9 and $7.8{\mu}g/mL$, respectively, that is comparable with vitamin C or butylated hydroxytoluene. Analysis of component in extract and fractionates suggested that the antioxidants in fractions are diverse and the active substances have glycosylated phenolic structure. Our results suggest that the aerial part of S. stolonifera could be used as the natural source of potential antioxidant.

• Journal of the Korean Dietetic Association
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• v.27 no.1
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• pp.45-58
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• 2021

This study evaluated the sanitation management standards for vegetable preparation processes without a cooking stage. The aerobic plate counts (APC), coliform counts, and Escherichia coli of the samples at each production step were analyzed, and microbial growth of the samples stored at different temperatures was measured. The validation was judged in accordance with the microbial criteria stipulated by the British PHLS. After washing and disinfection, the APCs of the two samples decreased to 3~4 log CFU/g in both seasons. Compared to the purchasing stage, the decrease in coliform counts was approximately 0~3 log CFU/g in both seasons; E. coli was not detected. The initial APC and coliform levels of two vegetable samples were 4~5 log CFU/g in both seasons, with an increase of 1 log CFU/g taking more than 6 h at 25℃ and 2 h at 35℃. More than 10 h at 25℃ and 6 h at 35℃ were required to increase the E. coli O157:H7 count by 1~2 log CFU/g for two seasoned samples. In conclusion, washing and disinfection effects and changes in microbial growth during room temperature storage were similar in the two vegetables. Despite the low sanitizing effect of the two vegetables, when cut vegetables were stored under the critical limit within 2 h at two different room temperatures, seasoned lettuce and chicory were at the 'satisfactory' or 'acceptable' levels of PHLS regardless of the storage temperatures. The validation of sanitation management standards applied to vegetable preparation with the no-cook step was approved.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.8
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• pp.1227-1232
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• 2016

Electrolyzed activated water (EAW) has been reported to exhibit strong bactericidal effects on foodborne microorganisms. However, the disinfection efficacy of EAW is affected by factors such as water source and hardness. This study investigated bactericidal effects of EAW against three gram-positive (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) and three gram-negative (Cronobacter sakazakii, Escherichia coli O157:H7, and Salmonella Enteritidis) foodborne pathogens. Six strains were treated with EAW prepared at different water temperatures (4, 22, and $40^{\circ}C$) for 15 min, and D-values were generated. The results show that the lowest D-values for Lis. monocytogenes by EAW produced at $4^{\circ}C$ and $40^{\circ}C$ were 6.60 and 1.57 min, respectively. The lowest D-value for Sal. Enteritidis by EAW produced at $22^{\circ}C$ was 2.92 min. D-values of all strains treated by EAW produced at $40^{\circ}C$ decreased significantly compared to those treated by EAW produced at $4^{\circ}C$ (P<0.05). These results demonstrate that applying EAW produced at warm temperature is more effective for reducing foodborne pathogens for food safety.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.24-29
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• 2012

A total of 187 samples of leafy vegetables and fruits were acquired at traditional markets and department stores in Seoul, Korea. Samples were tested for microorganism distributions and for the presence of pathogenic bacteria. The aerobic mesophilic counts ranged between 2.5 and 9.4 log CFU/g, with the highest count recorded from the dropwort. Counts of psychrotrophic microorganisms were as high as those of the mesophilic microorganisms. Total coliform populations between 1.0 and 7.8 log CFU/g were found in 90.9% of the samples. Microbiological counts for fruits were very low. $Escherichia$ $coli$ was isolated in 24 (12.8%) samples. $Staphylococcus$ $aureus$ and $Clostridium$ $perfringens$ contamination were found in 15 (8.0%) and 20 (10.7%) samples. $Salmonella$ species and $Listeria$ $monocytogenes$ were detected in 2.7 and 0.5% of samples, respectively. Among the total 187 samples, 8 samples were contaminated by more than two pathogens. $E.$ $coli$ O157:H7 was not detected in any of the samples. The microbial contamination levels determined in the present study may be used as the primary data to execute microbial risk assessment of fresh vegetables and fruits.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.312-318
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• 2013

This study validated microbiological hazards of ginseng farms at the cultivation stage and suggested recommendations to develop a good agricultural practices (GAP) model. A total of 96 samples were collected from cultivation environments (soil, irrigation water, and atmosphere), plants (ginseng and its leaf), personnel hygiene (glove, cloth, and hand) of 3 ginseng farms (A, B, and C) and were tested to analyze sanitary indicator bacteria (aerobic plate count, coliforms and Escherichia coli), major foodborne pathogens (E. coli O157:H7, Listeria monocytogenes, Salmonella spp., Staphylococcus aureus, and Bacillus cereus), and fungi. Total bacteria, coliform, and fungi in the 3 ginseng farms were detected at the level of 1.3~6.0, 0.1~5.0, and 0.4~4.9 v/g (or mL, hand, and $100cm^2$), respectively. Only irrigation water collected from one ginseng farm was confirmed to be E. coli positive. In case of pathogenic bacteria, B. cereus was detected at levels of 0.1~5.0 log CFU/g (or mL, hand, and $100cm^2$) in all samples, but other pathogen bacterias were not detected in any samples from all farms. Although E. coli were detected in irrigation water, the level of microbial for the three farms was lower than the regulation limit. According to the results, the ginsengs produced from the 3 farms were comparatively safe with respect to microbiological hazard. However, cross-contamination of bacteria from environments and workers to ginseng has been considered as potential risks. Therefore, to minimize microbial contamination in ginseng, GAP model should be applied for ensuring the safety of ginsengs.

• Journal of Food Hygiene and Safety
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• v.22 no.1
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• pp.45-51
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• 2007

The Collected 70 samples from 5 sandwich shops were analysed for the pathogenic bacteria such as Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus. As a result of Listeria monocytogenes and Saphylococcus aureus were detected in 1 sample, 11 samples, respectively. However, Escherichia coli O157:H7 and Salmonella spp. were not detected in anywhere. The antibiotics test of isolated bacteria was pelformed by the disk diffusion method from NCCLS. The resistance rate of Listeria monocytogenes isolates was confirmed 38.5% to 10 species such as Am, B, P, and Va for antibiotics of 26 species. MRSA was determinated 4 strains in S. aureus isolates. The resistance pattern of Staphylococcus aureus isolates were confirmed 36.4% to P Am OX B K E CXM, 18.2% to P Am B K E CXM B, 9.1% to P Am B K, 27.3% to P Am B, and 9.1% to Te B Nb. Therefore, continuous surveillance and monitoring for antibiotic resistance strains are demanded for prevention of increases in multiple antibiotic resistance strains.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.907-920
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• 2006

This study was conducted to investigate the inhibitory activity of Lactobacillus spp., Bacillus ssp., and calf fecal isolates against pathogenic Salmonella typhimurium, E. coli, Listeria monocytogenes, and Staphylococcus aureus. Among thirteen strains of Lactobacillus ssp. tested, Lactobacillus helveticus CU631 showed the highest inhibition against three pathogens, whereas Bacillus spp. showed a weak inhibitory activity. Four calf fecal isolates were identified as Lactobacillus pentosus CU13, CU05, Pediococcus pentosaceus CUR02, and Lactobacillus lactis ssp. lactis CUM14. The whole cell and cell wall components of L. rhamnosus CU02 and L. pentosus CU13 were active in the inhibition of L. monocytogenes. The medium components and levels, which affect on the inhibitory activity, were revealed as Tween 80 1.0%, peptone 3.0%, yeast extract 3.0%, glucose 3.0%, beef extract 3.0%, and NaCl 1.0～3.0%, respectively. Inhibitory activity of the supernatant culture medium was not affected by catalase and proteinase K treatment but affected by heat treatment at 80℃ and netralization, which implies that the inhibitory activity is due to the production of organic acids during the growth. L. pentosus CU13 and L. rhamnosus CU02 exhibited broad inhibition spectrum against 16 out of 21 strains including some pathogens. Oral administration of L. rhamnosus CU02 to the mice infected with E. coli O157:H7 was proven to be effective to recover their body weight during the experimental period.

• Childhood Kidney Diseases
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• v.8 no.1
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• pp.86-90
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• 2004

Hemolytic uremic syndrome(HUS) is characterized by acute renal failure, microangiopathic hemolytic anemia, and thrombocytopenia and the most common pathogen is Escherichia coli (E. coli) O157 : H7. Ischemic colitis, which rarely occurs in children, is due to the reduced local blood flow to the intestine, tissue necrosis and secondary bacterial infection. We describe a patient who was admitted with abdominal pain, vomiting and hematochezia, and diagnosed as ischemic colitis by barium enema. This patient showed hemolytic anemia, thrombocytopenia and progressive renal failure and was subsequently diagnosed as hemolytic uremic syndrome. After hemodialysis, the patient showed improvement of symptoms and resolution of renal failure and ischemic colitis.

• Korean Journal of Food Science and Technology
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• v.53 no.6
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• pp.799-808
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• 2021

This study was performed to investigate the extent of microbial contamination, the presence of enterotoxin genes, and the antibiotic susceptibility of Bacillus cereus in 58 red pepper plants and 43 environmental samples (soil, irrigation water, and gloves) associated with the plant cultivation. The detected counts of total aerobic bacteria, coliform bacteria, Escherichia coli, Bacillus cereus, and Staphylococcus aureus were lower in these samples, as compared to the regulations of standards for foods; moreover, pathogens, such as E. coli, E. coli O157:H7, Listeria monocytogenes, and Salmonella spp., were not detected. Genes encoding hemolysin BL enterotoxins (hblA, hblC, and hblD) as well as non-hemolytic enterotoxins (nheA, nheB, and nheC) were detected in 23 B. cereus specimens that were isolated from the test samples and had β-hemolytic activity. Interestingly, B. cereus is resistant to β-lactam and susceptible to non-β-lactam antibiotics. However, in this case, the isolated B. cereus specimens exhibited a shift from resistant to intermediate in response to cefotaxime and from susceptible to intermediate in case of rifampin, trimethoprim-sulfamethoxazole, vancomycin, clindamycin, and erythromycin. Therefore, the levels of B. cereus should be monitored to detect changes in antibiotic susceptibility and guarantee their safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1773-1778
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• 2009

Guava (Psidium guajava L.) contains high amount of vitamins and minerals, and its leaves have been reported to be very effective on reducing blood pressure. In this study, antimicrobial characteristics of extracts from four different parts of guava (fruit, branch, leaf, and seed) with four different solvents (methanol, ethanol, acetone, and water) were evaluated. Four targeted food-borne microorganisms were selected; two Gram negatives (Escherichia coli O157:H7 and Salmonella Typhimurium) and two Gram positives (Staphylococcus aureus and Listeria monocytogenes). By the paper disc method, guava extracts showed stronger clear hollow zone against Gram positive bacteria than Gram negatives in nutrient broth agar plate. Especially, extracts of branches and leaves showed significant antibacterial activity. Guava extracts also showed significant inhibition activity on the growth of Gram positive food-borne bacteria in nutrient broth. For example, S. aureus did not grow at all at 200 ppm of acetone extracts of guava branch and leaf. In the case of L. monocytogenes, the same concentration of acetone extracts of guava branch and leaf inhibited the growth 33.5% and 55.4%, respectively, at 32 hrs of incubation time. The results indicated that extracts of guava branch and leaf showed significant antibacterial activities against food-borne Gram positive microorganisms, and that guava branches, the byproducts of guava, might be a valuable resource for antibacterial materials.