• 한국식품영양학회지
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• 제12권6호
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• pp.564-568
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• 1999

Habituation to alkali condition and susceptibility to antimicrobial agents were investigated to determine methods t inactivation Escherichia coli O157:H7 associated with food poisoning. The investigation showed that Escherichia coli O157:H7growth at pH 9.0 The susceptibilities of Escherichia coli O157:H7 to 13 drugs examined were found highest in regad to saicin and ceftriaxone and lowest in regard to erythromycin and josamycin. No significant changes in minimal inhibitory concen-tration(MIC) values of bactericidal effect was found when saicin and ceftriaxone were irradiated with doses of 5-100KGy.

• Preventive Nutrition and Food Science
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• 제5권3호
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• pp.131-135
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• 2000

The inhibitory effect of various organic acids on the growth and survival of Escherichia coli O157:H7 in tryptic soy broth with 0.6% yeast extract at 37$^{\circ}C$ or 4$^{\circ}C$ was determined. Minimal inhibitory pHs of acetic acid, citric acid, fumaric acid, hydrochloric acid and lactic acid were 5.0, 4.0, 4.5, 4.0 and 4.5, respectively. Acetic acid (0.012 m) showed the strongest antimicrobial activity, based on the pH values or equivalent molar concentrations, followed by lactic acid (0.0006 M), fumaric acid (0.004M) and citirc acid (0.004 M), respectively, E. coli O157:H7 with an initial inoculum of {TEX}$10^{7}${/TEX} CFU/ml and {TEX}$10^{5}{/TEX} CFU/ml in tryptic soy broth supplemented with 0.6% yeast extract, acidified to target pH with citric, fumaric and lactic acids at 37$^{\circ}C$, was completely inactivated after 7 d and 5 d incubation, respectively, except for the acetic acid (9 d). The bactericidal effect decreased at the same pH when the incubation temperature a was reduced from 37$^{\circ}C$ to 4$^{\circ}C$. The pH values of 0.2% acetic (pH 5.1), 0.6% citric (pH 4.2) and 0.4% lactic acid (pH 4.3) in TSBYE were almost correspondent to the minimal inhibitory pH values on E. coli O157:H7 of acetic (pH 4.0), citric (pH 4.0) and lactic acids (pH 4.5).

• Journal of Dairy Science and Biotechnology
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• 제40권4호
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• pp.151-162
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• 2022

Although many developed countries (USA, Canada, and several EU countries) allow raw milk cheese to be aged more than 60 days, these countries have strict standards for the aging conditions, such as temperature, of raw milk cheese. Spiking experiments were conducted with Camembert cheese made from raw milk, to assess the microbiological safety of raw milk cheese aged for more than 60 days. We spiked Escherichia coli O157:H7 into raw milk with different inoculation levels (high, medium, and low). Camembert cheese was prepared from the inoculated raw milk, then aged in an incubator for up to 9 weeks (63 days). There were no significant differences in pH and water activity (aW) between uninoculated cheese and cheese samples inoculated with E. coli O157:H7 (p<0.05). The pH and aWof the Camembert cheese decreased throughout the storage period. In conclusion, E. coli O157:H7 did not affect the pH and aW of the cheese samples. Cell counts were conducted every week using the agar-plating method. Inoculated cells were completely eliminated, especially in Camembert cheese, after 60 days, and the reduction rate of cells was much faster in Camembert cheese.

• 한국식품위생안전성학회지
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• 제37권4호
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• pp.232-237
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• 2022

본 연구에서는 병원균인 Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium 그리고 Escherichia coli O157:H7을 이산화염소수와 전해수에 0분, 2분, 4분, 6분, 8분 및 10분간 반응시켜 이산화염소수와 전해수의 살균 효과를 확인하고, 그람 양성균(B. cereus, S. aureus)과 그람 음성균(S. Typhimurium, E. coli O157:H7)의 민감성 비교를 실시하였다. B. cereus, S. aureus, S. Typhimurium 그리고 E. coli O157:H7의 이산화염소수에서의 D값은 1.85±0.64, 2.06±0.85, 2.26±0.89 그리고 2.59±0.40분으로 나타났고 전해수의 경우 각각 2.13±0.32, 1.64±0.64, 1.71±0.32 그리고 1.86±0.36분으로 나타났다. 각 용액에 처리한 10분 간 모든 균주에서 꾸준한 감소 추세를 나타내었으며 각 용액에서 각 균주의 D값은 서로 유의적인 차이는 보이지 않았다 (P>0.05). 이산화염소수와 전해수의 살균력을 비교한 결과 D값은 유의적인 차이가 나타나지 않았으나, pH와 유효염소농도 모두 이산화염소가 전해수보다 낮은 값을 보였다. 살균·소독을 실시할 대상의 pH에 대한 민감성과 같은 특성을 고려하여 최적의 살균제를 선택하고, 최적의 농도를 결정하여 식품 산업에 적용하기 위한 자료로 활용될 것으로 기대된다.

• 한국미생물·생명공학회지
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• 제27권5호
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• pp.419-425
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• 1999

Prophylactic effects of Bifidobacterium longum HY8001, Korean isolate, against Escherichia coli O157:H7 and Salmonella typhimurium DT104 enteric infection were examined at four groups of specific pathogen free(SPF)-ICR mouse for each pathogen. B. longum HY8001+B. typhimurium DT104+B. longum HY8001(BL+ST+BL) group and B. longum HY8001+E. coli O157:H7+B. longum HY8001(BL+E+BL) group were fed with B. longum HY8001 before and after E. coli O157:H7 or s. typhimurium DT104 challenge, while B. longum HY8001+S. typhimurium DT104(BL+ST) and B. longum HY8001+e. coli O157:H7(BL+E) groups were fed with B. longum HY8001 only before E. coli O157:H7 or S. typhimurium DT104 challenge. E. coli O157:H7(E) and S. typhimurium DT104(ST) groups were challenged with each pathogen without B. longum HY8001 administration and control groups were administered with phosphate buffered solution(PBS). After the oral administration with B. longum HY8001(109cfu), th emice were challenged with E. coli O157:H7(2$\times$1010cfu) or S. typhimurium DT104(108cfu) and the mortality rate and the fecal shedding of challenged pathogen were also examined define the reactivity of the B. longum HY8001. Production of toxin neutralizing substance(s) of B. longum HY8001 was determined by cell cytotoxicity assay using Vero cells. Fecal shedding of th eS. typhimurium DT104 was significantly decreased in BL+ST+BL group fed with B. longum HY8--1 before and after challenge(p<0.05), while the fecal shedding s of S. typhimurium DT104 in BL+ST and St groups remained more than 106cfu. the protective effect of the B. longum HY8001 against E. coli O157:H7 was significantly high only in BL+E+BL group fed with b. longum Hy8001 before and after E. coli O157:H7 challenge from the result of fecal E. coli O157:H7 isolation rate, mortality rate, and intestinal contents culture to detect E. coli O157:H7. the mortality rate of the BL+e and E groups. The cytopathic effect (CPE) of the Vero cytotoxin (Shiga like toxin I & II) in Vero cell was neutralized in B. longum HY8001 culture supernatant added wells which indicate the presence of soluble Vero cytotxin neutralizing substance(s) in B. longum HY8001 culture suprnatant.

• 한국축산식품학회지
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• 제34권4호
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• pp.525-532
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• 2014

This study was designed to elucidate the effect of ozone exposure on the bacteria counts and oxidative properties of ground Hanwoo beef contaminated with Escherichia coli O157:H7 at refrigeration temperature. Ground beef was inoculated with 7 Log CFU/g of E. coli O157:H7 isolated from domestic pigs and was then subjected to ozone exposure ($10{\times}10^{-6}kg\;O_3h^{-1}$) at $4^{\circ}C$ for 3 d. E. coli O157:H7, total aerobic and anaerobic bacterial growth and oxidative properties including instrumental color changes, TBARS, catalase (CAT) and glutathione peroxidase (GPx) activity were evaluated. Ozone exposure significantly prohibited (p<0.05) the growths of E. coli O157:H7, total aerobic and anaerobic bacteria in ground beef samples during storage. Ozone exposure reduced (p<0.05) the CIE $a^*$ value of samples over storage time. The CIE $L^*$ and CIE $b^*$ values of the samples fluctuated over storage time, and ozone had no clear effect. Ozone exposure increased the TBARS values during 1 to 3 d of storage (p<0.05). The CAT and GPx enzyme activities were not affected by ozone exposure until 2 and 3 d of storage, respectively. This study provides information about the use of ozone exposure as an antimicrobial agent for meat under refrigerated storage. The results of this study provide a foundation for the further application of ozone exposure by integrating an ozone generator inside a refrigerator. Further studies regarding the ozone concentrations and exposure times are needed.

• 한국식품위생안전성학회지
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• 제12권4호
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• pp.304-309
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• 1997

A study was undertaken to determine the thermal inactivation of Escherichia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than pfosphate buffer (pH 7.1), with D values of 1.52~1.68 min at 6$0^{\circ}C$ and 1.51~1.63 min at 7$0^{\circ}C$ compared with 1.52~1.65 min at 6$0^{\circ}C$ and 1.26~1.61 min at 7$0^{\circ}C$ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (106 CFU/$m\ell$) was heated at 7$0^{\circ}C$. When E. coli O157:H7 was preheated at 48$^{\circ}C$ for 60 min in phosphate buffer before heating, D values were 1.28~1.60 min at 6$0^{\circ}C$, and 1.13~1.56 min at 7$0^{\circ}C$, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (109 CFU/$m\ell$), while ascorbic acid was no effect at low cell concentrations (109 CFU/$m\ell$).

• 한국식품위생안전성학회지
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• 제27권1호
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• pp.81-86
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• 2012

본 연구는 황련, 감초, 오미자 그리고 산수유 한약재 복합추출물의 $E.$ $coli$ O157:H7에 대한 항균효과와, 한약재 복합추출물과 염소산나트륨 합제의 $E.$ $coli$ O157:H7 감염 마우스에 대한 항균효과를 평가하기 위해 수행되었다. 한약재 복합추출물, CGSC10을 이용하여 $E.$ $coli$ O157:H7에 대한 항균효과 확인 시험을 수행한 결과, CGSC10 5, 10, 그리고 20%를 첨가한 배지에서 30시간 동안 배양한 후, $E.$ $coli$ O157:H7의 성장이 각각 34.7, 60.2, 그리고 76.4% 억제되는 효과가 관찰되었다. 또한, $E.$ $coli$ O157:H7을 감염시킨 마우스에 CGSC10, 염소산나트륨, 그리고 CGSC10와 염소산나트륨 합제(CGSCS10)를 음용수를 통해 투여한 결과, 투여 3일째부터, 모든 투여군에서 대조군과 비교하여 $E.$ $coli$ O157:H7의 균수가 유의성 있게 감소하였으며($p$ < 0.001), 투여 7일째에는, 10% CGSC10, 15mM 염소산나트륨, 그리고 CGSCS10을 투여한 군에서 대조군과 비교하여 $E.$ $coli$ O157:H7의 균수가 각각 27.1, 67.7, 그리고 83.3% 정도 감소하는 결과를 나타내었다. 따라서 본 연구의 결과로부터, CGSCS10을 $E.$ $coli$ O157:H7에 감염된 마우스에 음수로 투여할 경우, 감염증상을 완화 시킬 수 있을 것으로 기대된다.

• 대한한의학회지
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• 제25권3호
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• pp.191-202
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• 2004

Objectives : This study was designed to elucidate the synergistic cytotoxic mechanisms of the co-treatment of Gagamjengac-tang (GGJAT) and As₂O₃ in human lung cancer cell line, H-157. Methods : The combination of GGJAT and As₂O₃ synergistically augmented the cytotoxicity of GGJAT and As₂O₃ in H­157 cells. The cytotoxicity by the combination of these two drugs was revealed as apoptosis which was characterized by chromatin condensation and fragmentation in DAPI staining. Results : Antioxidant NAC completely blocked the apoptotic death of H-157 cells by GGJAT and As₂O₃. The apoptotic cytotoxicity of GGJAT and As₂O₃ was accompanied by the induction of DR4 and DR5 in RT-PCR. In addition, antioxidant enzymes such as SOD1, GSH synthetase and GSH reductase were also increased in H-157 cells treated with GGJAT and As₂O₃. However, of note, p53, Fas, FasL and TRAIL were not detected in H-157 cells treated with GGJAT and As₂O₃ by RT-PCR. Conclusions : These results suggest that the synergistic cytotoxicity of the co-treatment of H-457 cells treated with GGJAT and As₂O₃ may cause induction of death receptors DR4 and DR5 as well as reactive oxygen species.

• 한국식품과학회지
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• 제35권4호
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• pp.752-755
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• 2003

E. coli O157:H7에 대한 마늘즙액의 항균작용을 알아보기 위하여 마늘즙액의 처리량을 농도별 조건을 달리한 후 생균수 측정을 실시하였다. 마늘즙액 농도가 1%에서는 첨가하지 않았을 때에 비해 E. coli O157:H7의 생균수가 약간 줄어들었으나 마늘즙 처리량이 3%에서는 약 5 log, 마늘즙 처리량이 5%로 증가했을 때는 약 6 log의 생균수 감소를 보였다. 마늘즙의 식육내 항균작용 효과를 알아본 결과, 저육에서 3%, 6%, 10%의 마늘즙 농도별 차이에 따른 E. coli O157:H7에 대한 항균효과는 크게 다르지 않음을 알 수 있었다. 마늘즙의 가장 뚜렷한 저해 효과는 저장 9일에 나타나 약 2 log의 생균수 감소가 관찰되었다. 저장 9일 이후에는 E. coli O157:H7의 생균수가 다시 증가하는 것으로 미루어 마늘즙의 항균 효과가 소실되는 것으로 추정된다. 본 실험의 결과, 마늘의 조미료로써의 기능과 더불어 천연 방부제로써의 항균효과에 관한 기초 자료를 얻을 수 있었다.