• Korean Journal of Medicinal Crop Science
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• v.10 no.3
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• pp.206-211
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• 2002

For developing natural presevatives, essential oils of Mentha arvensis L. var. piperascens Malivaud and Agastache rugosa O. Kuntze were analyzed the composition of two oils and experimented on microorganism survival. Main components of Mentha arvensis oil were isomenthol (26.84%) and menthol (25.48%), and those of Agastache rugosa oil were estragole (79.83%) and limonene (4.13%) from GC-MSD analysis. Inhibition activities of Mentha arvensis oil against growth of Escherichia coli O157 : H7 ATCC 43895 and Salmonella typhimurium ATCC 7988 were observed from their clear zone $(9{\sim}14 mm\;&\;9{\sim}13\;mm)$, and that of Agastache rugosa oil were done from the clear zone $(13{\sim}20 mm\;&\;10{\sim}18\;mm)$ by concentration-dependent manner, respectively. In the inhibition test on CFU/ml of the microorganisms, both of the plant essential oils at concentration of 5 and 10 mg showed potent growth inhibition activities from 9 hour of incubation. Analysis using transmission electron microscope on E. coli also showed antimicrobial activities of the oils as deformation of the cell and loss of the intracellular materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1725-1732
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• 2015

The bactericidal effects of 642, 521, and 461 nm LED were investigated on Escherichia coli O157:H7 and Staphylococcus aureus strains in TSB with pH 7.2, 4.0, and 3.5 for 10 h at $15^{\circ}C$. The bactericidal effect of 461 nm blue LED was the most pronounced compared to 642 nm and 521 nm LEDs at pH 3.5. When E. coli was exposed to pH 3.5 with 461 nm LED, populations of E. coli O157:H7 ATCC 43894 and 35150 decreased by 4 and 5 log CFU/mL for 2 h, respectively. Populations of E. coli ATCC 8739 decreased by 5 log CFU/mL for 2 h. Further, S. aureus ATCC 27664, 43300, and 19095 were inactivated by 4, 5 and 5 log CFU/mL for 2 h, respectively, at pH 3.5 with 461 nm LED. In conclusion, combined treatment with 461 nm LED and acidic conditions at low-temperature ($15^{\circ}C$) showed the greatest antimicrobial effects. This study suggests that LEDs may be potentially used as a method to maintain the safety of the food preservation technology.

• Korean Journal of Food Science and Technology
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• v.44 no.1
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• pp.114-120
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• 2012

The purpose of this study was to evaluate the antibacterial activities of chopping boards made of various materials such as three antibiotic plastics, a general plastic, and various woods (red pine, rubber tree, cypress, birch, and bamboo) using zone inhibition assay and real-time PCR. Wood chopping boards showed high antimicrobial activity against Vibrio vulnificus, while plastic chopping boards showed high antimicrobial activity against Escherichia coli O157:H7, Salmonella Typhimurium, and Staphylococcus aureus. Bamboo chopping board among the wood chopping boards showed the highest antimicrobial activity against five foodborne bacteria such as E. coli O157:H7, S. Typhimurium, Vibrio cholerae, and V. vulnificus. These results may be helpful in the selection of a chopping board with high antimicrobial activity and in the application of hygiene procedures for prevention of cross-contamination.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1613-1618
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• 1999

Extracts of Citrus sudachi juice and peel were obtained by several organic solvents such as hexane, acetone, ethyl acetate and methanol. Their antimicrobial spectrum were determined against 14 strains of gram positive and 4 strains of gram negative bacteria by paper disk method and minimal inhibitory concentration (MIC) was also obtained. Antimicrobial activities of solvent extracts from Citrus sudachi juice showed stronger than those of solvent extracts from peel. Acetone extract from juice showed the strongest antimicrobial activity among extracts, but the hexane extract did not show antimicrobial activities on tested target strains. The MIC was differant among tested strains; i.e. 0.5% (v/v) to Bacillus subtilis, 1% to Pseudomonas fragi, 1.5% to Listeria monocytogenes and Escherichia coli O157:H7, 2% to Propionibacterium acnes and Salmonella typhimurium, and 2.5% to Staphylococcus aureus.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.526-533
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• 2019

The purpose of this study was to investigate hazardous microorganisms in mixed baby leafy vegetables and various baby leafy vegetables used as raw materials for fresh-cut produce in spring and summer. To estimate microbial loads, a total of 298 samples including 181 samples of mixed baby leafy vegetables purchased in a Korean market and 117 samples of various baby leafy vegetables from distribution companies were collected. Fecal indicators (coliform and Escherichia coli) as well as food-borne pathogens (E. coli O157:H7, Salmonella spp., Staphylococcus aureus) were enumerated. As a result, the mixed baby leafy vegetable samples showed significantly higher (P<0.05) coliform bacteria numbers in summer (5.59±1.18 log CFU/g) compared to spring (3.60±2.53 log CFU/g). E. coli was detected in 1.3% (1/79) and 42.2% (43/102) of samples collected in spring and summer, respectively. Only one sample collected from a market in spring was contaminated with S. aureus. In the experiment with baby leafy vegetables, the number of coliforms detected in baby leafy vegetables cultivated in soil in spring was 1.15±1.95 log CFU/g, and that in summer was 4.09±2.52 log CFU/g. However, the number of coliforms recovered from baby leafy vegetables cultivated in media was above 5.0 log CFU/g regardless of season. Occurrences of E. coli were 44.4% (12/27) and 19.0% (4/21) for baby leafy vegetables cultivated in soil and media, respectively. However, E. coli O157:H7 and Salmonella spp. were not detected. These results are in relation to microbial loads on mixed baby leafy vegetables associated with raw materials. Therefore, it is necessary to develop and implement hygienic practices at baby leafy vegetable farms to enhance the safety of fresh produce.

• Journal of Environmental Health Sciences
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• v.32 no.1 s.88
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• pp.77-88
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• 2006

This study were conducted to investigate the microbial contamination level in 5 tomato farms in Western Gyeongnam. A total of 130 samples was examined for sanitary indicator bacteria, such as aerobic plate count (APC), coliforms, and Escherchia coli, and pathogenic bacteria such as E. coli O157:H7, Salmonella spp., Staphylococcus aureus, and Listeria monocytogenes. APC and coliform count ranged $0\~6.62\;and\;0\~4.52 log_{10}\;CFU/(ml,\;g,\;100\;cm^2,\;hand)$, respectively, and $32.5\%$ were contaminated with E. coli. Especially, most of the samples from employees are high as above $4.0\;log_{10}\;CFU/(ml,\;g,\;100\;cm^2,\;hand)$ in APC. S. aureus, detected at $10.7\%$, was found in employees' hands, irrigation water, and hydroponic solution. whereas E. coli $O157:H7$, Salmonella spp, and L. monocytogenes were not detected. These results will provide fundamental microbiological information for introduction of good agricultural practice (GAP)system in tomato farms.

• Korean journal of food and cookery science
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• v.27 no.4
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• pp.55-65
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• 2011

This study was performed to analyze the microbiological hazards of ready-to eat sandwiches and to evaluate the effect of implementing a hazard analysis and critical control points (HACCP) for quality improvement of ready-to-eat sandwiches. In total, 174 samples were examined for the microbiological hazard analysis. About 37.4% of the samples had an aerobic plate count ${\geq}$6 log CFU/g, and the numbers of coliforms exceeded 3 log CFU/g in 82.2% of the samples. Additionally, Staphylococcus aureus, E. coli, and Salmonella spp. were detected in 10.3%, 4.6%, 1.1% of sandwiches, respectively. In contrast, E. coli O157:H7, and Listeria monocytogenes were not detected in any of the samples. The results of the microbiological verification after implementing a HACCP throughout the production process indicated that S. aureus, E. coli, Salmonella spp., E. coli O157:H7, and L. monocytogenes were not detected in any of the samples. Consequently, implementing a HACCP is effective for quality improvement of ready-to-eat sandwiches.

• Korean journal of food and cookery science
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• v.19 no.5
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• pp.555-561
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• 2003

The purpose of this study was to analyze the microbiological hazards of dried fish (Jwieochae, Ojingeochae and Bugeochae), and to apply pretreatment methods to increase the safety of cooked dried fish within foodservice establishments. Microbiological inspections were conducted on Total Plate Count, Coliforms, E. coli, E. coli O157:H7, Staphylococcus aureus, Salmonella spp. and Listeria monocytogenes. The study results are summarized as follows. According to the Hazard analysis, there are many problems showing high numbers in terms of Total Plate Count and Coliforms, which were both well over acceptable standard levels. E. coli and Staphylococcus aureus were detected at certain foodservice establishments, while E. coli O157:H7, Salmonella spp. and Listeria monocytogenes were not detected at all. By applying various pretreatment methods, such as washing, blanching, pan frying and microwave heating, the levels of microbiological hazards were able to be controlled and lowered. Blanching was the most effective method, followed by panfrying, microwave heating and washing. The Total Plate Counts gradually decreased with increasing number of times washed and seconds panfried. From these results, it is concluded that to guarantee food safety, cooked dried fish raw materials should be kept hygienically and appropriate pretreatment methods applied before cooking.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.408-414
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• 2014

The antimicrobial and antioxidant activities of different cultivars and parts of broccoli were investigated. The screening of antimicrobial activities for the floret and leaf extracts of 11 cultivars against selected gram positive (Staphylococcus aureus and Listeria monocytogenes) and gram negative bacteria (Escherichia coli O157:H7 and Salmonella enteritidis) were conducted. The AMG cultivar showed the highest antimicrobial activity against S. aureus with the floret and leaf extracts (12.83 and 13.00 mm). Antibacterial activity against L. monocytogenes was strongest with floret extract of NJ cultivar (13.58 mm) and leaf extract of YDR cultivar (13.92 mm). Moreover, the size of inhibition zone against L. monocytogenes was bigger than those of 4 kinds of pathogenic bacteria. Both floret and leaf extracts of Grd cultivar showed the highest antimicrobial activity against E. coli O157: H7, but there was no difference between floret and leaf extracts. Floret extract o f NJ cultivar and leaf extract of NY and 0c cultivars were effective against S. enteritidis whereas leaf extract exhibited better antimicrobial effect than floret extract. These results showed that floret extract of NJ and leaf extract of 0c had the highest antioxidant activity which was 39.90 and 43.64%, respectively. The antioxidant activity of leaf extract was 1.5 times higher than that of floret extract. All cultivars except NJ showed that electron donating ability of leaf extract was higher than that of floret extract.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.71-78
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• 2002

With the incidence of antibiotic resistant bacteria there is increasing interest in natural products such as herb extract and probiotics to control antibiotic resistant bacteria. This study was focused on the determination of antimicrobial activity of Opuntia ficus-indica var. saboten against Salmonella enetrica serovar Enteritidis (S. enterifidis), S. enterica serovar Typhimurium (S. Typhimurium) DT 104 and Escherichia coli 0157:H7. Though bactericidal effect of 0. ficus-indica var. saboten was not observed, it had significant inhibitory activity against Salmonella spp. and E. coli O157:H7 on the Moulter Hinton agar containing its solution dissolved in deionized water. To investigate the antimicrobial activity in vivo, mice were challenged with 5. Typhimurium DT104 (3.7$\times$108 cfu/mouse) after pre-feeding 0. ficus-indica var. saboten solution. The fecal shedding of S. Typhimurium DT104 was more dramatically decreased and not detectable in feces and intestines 3 days after challenge in mice fed with 0. ficus-indica var. saboten. Antibody responses of the intestinal IgA were also significantly increased in mice fed with 0. ficus-indica var. saboten. These findings suggest that Opuntia ficus-indica var. saboten decreased the shedding of S. Typhimurium DT104 in vitro and also in the gastrointestinal tract in mice. In addition, administration of the product might enhance the mucosal immune response against S. Typhimurium DT 104. In conclusion, Opuntia ficus-indica var. saboten might be useful to control antibiotic resistant bacteria in vivo and in vitro.