논문 상세보기
pp.45-52
본 연구에서 녹차의 물추출물과 에탄올추출물, 합성보존료인 potassium sorbate와 sodium benzoate의 식중독세균(Listeria monocytogenes, Staphulococcus aureus, Escherichia coli, Salmonella typhimurium)에 대한 항균활성을 비교하였다. 녹차추출물과 보존료를 0∼2%(w/v) 첨가한 tryptic soy broth(TSB)에 균액을 약 105 CFU/ml가 되게 접종하여 35℃에서 24∼48시간 배양하여 생균수를 측정한 후 세균의 생존곡선으로부터 최소저해농도(MIC)와 최소사멸농도(MBC)를 구하였다, 식중독세균에 대한 녹차추출물의 항균활성은 pH가 높을수록 컸으나 보존료의 항균활성은 pH가 낮을수록 증가하였다. S. aureus는 녹차추출물에 의하여 가장 쉽게 사멸되었으나 보존료에 대하여느 강한 내성을 나타내었다. pH 5.5∼7.0에서 녹차추출물들의 S. aureus에 대한 MIC는 0.25∼0.35%, MBC는 1.0∼2.0%였다. Potassium sorbate와 sodium benzoate의 S. aureus에 대한 MIC는 pH 5.5∼6.0에서 0.52∼0.98%였으나 pH 7.0에서는 세균의 증식이 억제되지 않았다. pH 6.5∼7.0에서 녹차추출물들의 S. typhimurium에 대한 MIC는 0.46∼1.62%였으나 pH5.5에서는 세균 증식이 억제되지 않았다. S. typhimurium에 대한 보존료의 MIC는 pH5.5∼6.0에서 0.30∼1.30%였으며 pH 5.5 potassium sorbate 2.0% 농도에서 이 세균은 사멸되었다. L. monocytogenes를 제외한 모든 시험균주는 pH7.0에서 1.0∼2.0%의 녹차 물추출물과 에탄올추출물에 의해 사멸되었다.
Survival of pathogenic bacteria(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate(PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containning 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 10 exp (5) CFU/ml of pathogenic bacteria and incubated at 35℃ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.25∼0.35% and MBCs of the extracts were 1.0∼2.0% at pH 5.5∼7.0. The MICs of PS and SB to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 6.5∼7.0 and non inhibitory at pH 5.5. The MICs of PS and SB to S. typhimurium were 0.30∼1.30% at pH 5.5∼6.0 and 2% PS was bactericidal at pH 5.5. 1.0∼2.0% of GTW and GTE were bactericidal to all strains tested except L. monocytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.
