The objective of this study was to investigate and evaluate microbial contamination levels of leafy greens (perilla leaf and lettuce) and its distributing conditions at different seasons (Feb, May, Aug, and Nov of the year 2011) in order to provide insight into any potential health hazards associated with consumption of these commodities. Leafy greens were collected from a farm located in Geumsan, Chungnam and wholesale markets (WM) and traditional markets (TM) located in Suwon. At the same time, temperature and relative humidity fluctuations experienced by the leafy greens during distribution from the farm to the distribution center were measured by a data logger. The contamination levels of perilla leaf and lettuce were determined by analyzing total plate count. Coliform groups, Bacillus cereus, Escherichia coli, Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes and Staphylococcus aureus were determined. The contamination levels of total aerobic bacteria, coliform groups and B. cereus in both vegetables sampled during May and August found to be higher than those sampled during February and November. E. coli O157:H7, Salmonella spp., L. monocytogenes were not detected in the vegetables analyzed in this study. There were no significant trends between samples at WM and TM in the contamination levels. Relative humidity of vegetables distributed from the farm to the distribution center showed over 90% during distribution regardless of measured seasons. In the case of background microflora on leafy greens, the density was significantly increased at 20, 30 and 37oC during storage of 24h. E. coli O157:H7 and B. cereus inoculated on the leaves also showed similar increases in the storage tests. The microbial contamination levels determined in this study may be used as the fundamental data for microbial risk assessment.

ABSTRACT
 서 론
 재료 및 방법
  상추와 들깻잎 시료 수집
  들깻잎 유통 온·습도 조건 조사
  위생지표세균 및 식중독세균 오염도 조사
  들깻잎과 상추의 보관온도에 따른 위생지표세균과 식중독세균의 밀도 변화 조사
  통계적 분석
 결과 및 고찰
  시기별 들깻잎의 유통 온·습도
  들깻잎과 상추의 수집 시기 및 유통단계별 위생지표세균및 식중독세균 오염도
  들깻잎과 상추의 보관온도에 따른 backgroundmicroflora 및 식중독세균 밀도 변화 조사
 요 약
 감사의 글
 참고문헌

• 김원일(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Won-Il Kim
• 정향미(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Hyang-Mi Jung
• 김세리(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Se-Ri Kim
• 박경훈(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Kyeong-Hun Park
• 김병석(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Byung Seok Kim
• 윤종철(농촌진흥청 국립농업과학원 농산물안전성부 유해생물팀, Microbial Safety Team, Department of Crop Life Safety, National Academy of Agricultural Science, RDA) | Jong-Chul Yun
• 류경열(농촌진흥청 연구정책국 연구성과관리과, R&D Performance Evaluation & Management Division, Research Policy Bureau, RDA) | Kyoung-Yul Ryu Correspondence to