• Journal of Food Hygiene and Safety
• /
• v.38 no.1
• /
• pp.31-36
• /
• 2023

This study was conducted to evaluate the efficacy of sodium hypochlorite in eliminating Escherichia coli strains from leafy green and stem vegetables, which are frequently sold at community service centers. A cocktail of non-pathogenic E. coli and enterohaemorrhagic E. coli (E. coli O157:H7) was used to artificially contaminate the vegetables (initial numbers of bacteria 7-8 log CFU/g). The contaminated vegetables were soaked in sodium hypochlorite for 5 min and then washed three times with running water. After the treatment, number of viable bacterial cells on the vegetables was estimated. Sodium hypochlorite treatment reduced the E. coli population by 1-2 log CFU/g on leafy green and stem vegetables, a significant reduction from the initial number. Further, sodium hypochlorite showed better antimicrobial efficacy for leaves with a larger surface area, less roughness, and softness. There was no significant difference in the antimicrobial effect between 100 and 200 mg/kg of sodium hypochlorite. Therefore, it is not necessary to increase sodium hypochlorite concentration than the level suggested in the school meal hygiene management guidelines. However, sodium hypochlorite treatment is not sufficient to achieve a safe level of microorganisms on leafy green and stem vegetables since they generally have a high abundance of microorganisms on their surface. Thus, an alternative cooking method for fresh leafy green and stem vegetables in summer should be developed to ensure they are safe for consumption.

• Korean journal of food and cookery science
• /
• v.28 no.2
• /
• pp.175-182
• /
• 2012

In this study, antibacterial activity and cytotoxicity of the extracts from pericarp and seed of $Vitis$ $coignetiea$, which were extracted with 0.1% HCl-60% ethanol, were analyzed. The antibacterial activity of the extracts was determined by paper disc diffusion method against food spoilage and food-borne pathogens. The pericarp extract showed high antibacterial activity against $Bacillus$ $cereus$, $Escherichia$ $coli$ O157:H7, and $Pseudomonas$ $aeruginosa$, and the seed extract represented the high antibacterial activity against $B.$ $cereus$, $E.$ $coli$ O157:H7, and $Staphylococcus$ $aureus$. The cytotoxicity of the $Vitis$ $coignetiea$ extract against human cancer cells was determined using the MTT assay and SRB assay. The pericarp extract represented strong growth-inhibition activity against G361 and Hep3B cells and the seed extract greatly inhibited the growth of HeLa and G361 cells in the MTT assay. In addition, the pericarp extract displayed a high inhibition activity against the growth of AGS cells and the seed extract greatly inhibited the growth of HeLa, Hep3B, and MCF7 cells in the SRB assay. Especially, the cytotoxicities of the seed extract against HeLa were significantly higher than those of the extract against other cancer cells at all test concentrations. This study demonstrates that the extract from pericarp and seed of $Vitis$ $coignetiea$ possess high antibacterial activity and cytotoxicity.

• Journal of Food Hygiene and Safety
• /
• v.22 no.2
• /
• pp.77-81
• /
• 2007

Antimicrobial activity of both fresh Prunus mume and Prunus mume liqueur byproduct (PLB), generated after producing Prunus mume liqueur were examined against various pathogeinc bacteria such as Listeria monocytogenes Scott A, Listeria monocytogenes ATCC 19115, Bacillus cereus KCCM 11341, Staphylococcus aureus KCCM 12255, Pseudomonas fluorescens ATCC 21541, Escherichia coli O157:H7, Salmonella Typhimurium ATCC 14028, and Shigella sonnei. PLB showed strong antibacterial effects against tested pathogenic bacteria.L. monocytogenes ATCC 19115, B. cereus KCCM 11341, S. sonnei, and E. coli O157:H7 were not detected in trytpic soy broth containing 1% of prunus mume or PLB after 24-hour incubation at $37^{\circ}C$, respectively. Prunus mume showed higher antimicrobial activities than that of PLB against tested pathogens.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.3
• /
• pp.379-389
• /
• 2008

This study was conducted to assess the microbiological quality of raw and cooked foods served in the elementary school food service. Raw and cooked food samples were collected from 11 selected elementary schools in both June to July and September to October of 2005. Petrifilm plates were used to determine (in duplicate) total aerobic colony counts (PAC), Enterobacteriaceae (PE), coliform counts (PCC), and E. coli counts (PEC). Heavy contamination of Enterobacteriaceae (from 0.08 to 7.40 log CFU/g) and total coliform (0.50 to 6.52 log CFU/g) were observed in raw materials and cooked foods. Escherichia coli (E. coli) were detected in the sample of currant tomato (3.70 log CFU/g), sesame leaf (3.59 log CFU/g), dropwort (0.20 log CFU/g), crown daisy (3.15 log CFU/g), parsley (3.00 log CFU/g), peeled green onion (1.74 log CFU/g), frozen pork (0.65 log CFU/g), frozen beef (0.20 or 1.50 log CFU/g), chicken (1.78 log CFU/g), and young radish leaf seasoned with soybean paste (1.24 log CFU/g). Multiplex PCR system was used to determine the food-borne pathogens: Salmonella spp., Bacillus cereus (B. cereus), E. coli O157:H7, Staphylococcus aureus, Listeria monocytogenes (L. monocytogenes), Vibrio parahaemolyticus, Campylobacter jejuni (C. jejuni), Shigella spp., B. cereus was detected in 19 samples of raw materials and 8 samples of cooked foods. With regard to quantitative analysis, B. cereus counts exceeded 5.46, 3.48 and 1.79 log CFU/g in sesame leaf, peeled green onion and seasoned mungbean jelly, respectively. E. coli O157:H7 was detected on 2 samples of frozen beefs, and its biochemical characteristics of one beef sample was confirmed with API 20E kit (93.7%). L. monocytogenes was detected in fried rice paper dumpling, but the presumptive colonies were not detected onto the conventional plate. C. jejuni was detected in peeled & washed onion.

• Korean journal of food and cookery science
• /
• v.16 no.1
• /
• pp.40-46
• /
• 2000

The sensitivity of various pathogenic bacteria(Listeria monocytogenes, Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli O157:H7 and Salmonella typhimurium) to the pine needle and green tea extracts was tested. Water extract of pine needle(PNW), 70% ethanol extract of pine needle(PNE), water extract of green tea(GTW) and 70% ethanol extract of green tea(GTE) were prepared for the test of antibacterial activty. Tryptic soy broth(TSB) containing 0∼2%(w/v) of pine needle and green tea extracts were inoculated with 10$\^$5/∼10$\^$6/ cells/ml of each bacterium and incubated at 35$\^{C}$ for 24 hours. The standard plate count method was used to measure the inhibitory effect of the extracts. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) were derived from the survival curves of pathogenic bacteria. Antibacterial activities of the pine needle and green tea extracts were compared with that of sodium benzoate, a preservative, by clear zone test. L. monocytogenes, S. aureus and A. hydrophila were completely inhibited at 0.4∼1.6% level while E. coli and S. typhimurium were very resistant to the pine needle extracts. Green tea extracts completely inhibited all strains tested at 0.2∼1.0% level and bactercidal to all strains except L. monocytogenes at 0.5∼2.0% level. Antibacterial activities of pine needle and green tea extracts were stronger than that of sodium benzoate. The order of antibacterial activities of pine needle and green tea extracts to the pathogenic bacteria was GTE > GTW > PNE > PNW. This result suggests that green tea extracts can be used as an effective natural antibacterial agent in food.

• Biomedical Science Letters
• /
• v.26 no.4
• /
• pp.383-388
• /
• 2020

Ingestion of food contaminated with microorganism, if not always, could lead to severe health problem. Preservatives has been added to food to prevent food from being contaminated with microorganism. But, these have potential to threaten the health. Therefore, much effort has been taken to find the safe materials showing the anti-microbial activity. In this study, we investigated the anti-bacterial activity of Oenothera lamarckiana aerial part extract against eight bacteria strain. In paper disc assay, extract inhibited the growth of Staphylococcus aureus, Methicillin-resistant S. aureus, Bacillus cereus and Shigella dysenteriae at 200 μg/disc, but not against Escherichia coli, E. coli O157:H7, Salmonella Typhi and S. enteritidis. Minimum inhibitory concentration (MIC) against Staphylococcus aureus, Methicillin-resistant S. aureus, Bacillus cereus and Shigella dysenteriae is 250, 250, 500 and 500 μg/mL, respectively. Compared with reported MIC of other plant resources, O. lamarckiana aerial part extract showed the relatively high anti-bacterial activity. O. lamarckiana aerial part could be suitable for the preservative development. But, it still remains to be studied to evaluate safety and so on.

• Korean Journal of Food Science and Technology
• /
• v.43 no.4
• /
• pp.513-517
• /
• 2011

The effects of nonthermal plasma treatments against Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes living on polystyrene (PS), sausage casings, and smoked salmon were investigated. Inoculated PS, casings, and salmon were treated with nonthermal plasma generated with helium (5 L/min) or with both helium (5 L/min) and oxygen (100 mL/min) at 60 Hz and 30 kV/cm for 2, 5, or 10 min. S. Typhimurium exhibited the highest sensitivity to the helium-used treatment. The greatest reduction (3.9${\pm}$0.8 log$CFU/cm^2$) was observed with L. monocytogenes on PS after the treatment with the mixed gas for 5 min. The treatment with the mixed gas inhibited L. monocytogenes on casings and salmon by 0.5${\pm}$0.3 log$CFU/cm^2$ and 1.0${\pm}$0.3 log CFU/g, respectively. Different treatment times did not result in different reductions of L. monocytogenes on both casings and salmon. The types of treatment gas and material of contamination need to be considered for evaluating the antimicrobial effects of nonthermal plasma treatments.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2003.05a
• /
• pp.93-94
• /
• 2003

In recent, there are many report about nonthermal disinfection using electorlyzed water, Also, foodborne illnesses associated with pathogenic bacteria such as Listeria monocytogenes and Escherichia coli O157:H7 have raised concerns about the adequacy of disinfectants (Kim et at., 2000). Foodborne pathogens in vegetables and kitchen apparatus are not easy to disinfect but also hard to use chemical compounds for disinfection. (omitted)

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2000.05a
• /
• pp.52-57
• /
• 2000

• Korean Journal of Veterinary Service
• /
• v.22 no.4
• /
• pp.411-418
• /
• 1999

In this studies, the ability of chlorine and lactic acid to reduce bacterial population of the pathogenic microorganisms were examined on artificially inoculated chicken skin. About 10$^{5}$ cells of staphylococcus aureus, salmonella enteritidis, listeria monocytogenes and escherichia coli O157:H7 were inoculated in chicken skin. The contaminated samples were washed for 1 min with sodium hypochlorite solutions that contained 2, 5, 10, 20 and 50mg/$\ell$ available chlorine and counted number of the agents. Viable population were no significantly difference (p$\geq$0.05) between concentration of chlorine and strains of the pathogens. In the samples inoculated with pathogens were washed in 20mg/$\ell$ chlorine and then stored at $^5{\circ}C$ for up to 10 days, the initial counts of psychrotrophs and aerobic plate counts were 4.02 to 4.36 log cfu/$\textrm{cm}^2$ and increased slightly in course of time. But 10 days after, the pathogens were a little reduced from 3.66~4.91 log cfu/$\textrm{cm}^2$ to 2.54~4.66 log cfu/$\textrm{cm}^2$. In the case of washed skin with solution of 20mg/$\ell$ chlorine and 0.5% lactic acid then store at $^5{\circ}C$ for up to 10 days, population of psychrotrophs and aerobic plate counts on chicken skin were markedly reduced immediately after treatment, but the numbers of contaminants were slightly increased after 6 and 8 days. Specifically, numbers of St aureus, S enteritidis, L monocytogenes and E coli O157:H7 were reduced to 0.5, 0.4, 0.3 and 1.15 log cfu/$\textrm{cm}^2$ after 10 days of storage, respectively, on aerobic plate counts.