차 중에 있는 살균제 tridemorph의 잔류량을 검사하기 위해 LC-ESI-MS/MS를 이용한 정확하고 감도가 좋은 분석방 법을 개발하였다. Tridemorph 잔류물은 샘플을 수화한 후 acetonitrile로 추출하고, NaCl을 이용한 액-액 분배, NH2 카트리지 정제를 거쳐 기기분석을 수행하였다. 직선성은 0.02~1.0 μgmL−1 범위에서 상관계수(r2) 0.9999로 높은 직선 성을 보였다. 0.02와 0.05 mgkg−1 처리수준으로 회수율을 실험한 결과는 75.0~84.7% 이었으며, 상대표준편차는 10% 미만이었다. 분석방법의 검출한계와 정량한계는 각각 0.01 와 0.02 mgL−1 이었다. 이러한 결과들을 통해 확립된 분석법은 차 중 tridemorph의 잔류량 분석에 적합함을 확인할 수 있었다.

Recently pathogenic E. coli is one of the main foodborne pathogens resulting in many patients in Korea. To understand the characteristics of pathogenic E. coli outbreaks in Korea, the epidemiological investigation reports of pathogenic E. coli outbreak in 2009 (41 reports) and in 2010 (27 reports) were collected in the web site of the Korea Centers for Disease Control and Prevention, reviewed and analysed in this study. The main places of the pathogenic E. coli outbreaks were food catering service area (64.8%) and restaurants (25.0%). The main type of the pathogens were EPEC (44.7%) and ETEC (34.2%). EAEC and EHEC was responsible for 10.5 and 9.2%, respectively. Eight of 68 outbreak cases were caused by more than 2 types of pathogenic E. coli which implicates the complicated contamination pathways of pathogenic E. coli. The incidence rate of pathogenic E. coli was 33.6 ± 30.5% and the main symptoms were diarrhea, stomach ache, nausea, vomiting, and fever etc. The two identified food sources were identified as frozen hamburger pattie and squid-vegetable mixture. To improve the food source identification by epidemiological investigation, food poisoning notification to the agency should not be delayed, whole food items attributed the outbreak should be collected and detection method of the various pathogenic E. coli in food has to be improved. In conclusion, the characteristics between the EHEC outbreaks in the western countries and the EPEC or ETEC outbreaks in Korea needs to be distinguished to prepare food safety management plan. In addition, the development of the trace back system to find the contamination pathway with the improved detection method in food and systemic and cooperative support by the related agencies are necessary.

This study was conducted to investigate the microbiological contamination levels in rice cakes and rice flour due to climate change in three areas classified to their temperature and precipitation. We investigated the contamination levels of total aerobic bacteria, coliforms, Escherichia coli, Bacillus cereus, Staphylococcus aureus, Clostridium perfringens of rice flour and 3 rice cakes such as Garaetteok, Sirutteok and Gyeongdan. Contamination levels of total aerobic bacteria in rice flour were 4.9 log CFU/g. In a total of 70 rice flour, yeasts & molds and coliforms were detected in 42 and 52 samples at the levels of 43 CFU/g and 1.29 log CFU/g, respectively. S. aureus were detected in only 1 rice flour (1.66 log CFU/g) out of 70. In an investigation of contamination levels in rice cakes, the population of total aerobic bacteria were highest in Gyeongdan (5.18 log CFU/g) and coliforms were highest in Gareattock (2.93 log CFU/g). There was no detection of E. coli and B. cereus except for only 1 Gareattock (1.20 log CFU/g). There were no differences of contamination levels among the three areas. If constant monitoring of rice cakes and rice flour is conducted on the basis of this study, it is expected to be able to analyze the change of contamination levels in rice cakes and rice flour due to climate change.

The purpose of this study was to evaluate microbiological contamination of fresh-cut produce salads and raw cabbage toward climate change. Total aerobic bacteria, coliform and Escherichia coli were monitored to get the contamination levels and E. coli O157:H7, Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes and Salmonella spp. to detect pathogens with risk of foodborne disease from samples. Collection of 360 samples (180 fresh-cut produce salads and 180 raw cabbage), including 60 samples from each area after setting 3 areas depending on annual temperature and annual rainfall. As a result, total aerobic bacteria and coliform group were different was performed areas in raw cabbage but there was no difference between areas in fresh-cut produce salads. In addition foodborne pathogens including E. coli were not isolated from fresh-cut produce salads.

This study was conducted to evaluate microbial contamination levels of Korea traditional rice cakes such as Sirutteok, Garaetteok and Gyeongdan in the manufacturing process and environment. The microbial contamination levels such as total aerobic bacteria, fungi, coliforms, Escherichia coli, Staphylococcus aureus, Bacillus cereus and Clostridium perfringens of rice cake products were analyzed. The contamination levels of total aerobic bacteria, coliforms, fungi and B. cereus in raw materials were in the range of 2.4~4.5, ND~1.9, 1.2~2.1 and 1.0~2.1 log CFU/g, respectively. The microbial contamination levels of total aerobic bacteria, coliforms, fungi and B. cereus in manufacturing process of rice cakes were increased in the soaking and grinding steps and were decreased in steaming step. E. coli, S. aureus and C. perfringens were not detected in any manufacturing process and environment. The microbial contamination levels of raw materials and final products of rice cake were suitable for microbial safety standard in Korea. However, the manufacturing environment such as equipments and employee's sanitation were in trouble for microbial safety. The results of this study suggest that safety education for personal hygiene and safety management in processing environment are continuously required to assure safety in working environment and employee's individual hygiene.

Vibrio parahaemolyticus (V. parahaemolyticus) has been recognized as a significant food-borne pathogen around the world. In this study, we investigated the prevalence and antimicrobial resistance of V. parahaemolyticus isolated from raw fishes. A total of 64 samples of raw fishes purchased from a traditional seafood market in Seoul, Korea. were examined for the presence of V. parahaemolyticus using intestines, gills, and fins. Twenty five grams of all samples were enriched in 225ml of alkaline peptone water at 37℃ for 24h and then streaked onto thiosulfate citrate bile sucrose agar. Suspected colonies were inoculated into triple sugar iron agar for biochemical screening test and were finally confirmed with API 20NE strip. Antimicrobial resistance tests were performed with disc diffusion method in accordance with National Committee for Clinical Laboratory Standard. Thirty three V. parahaemolyticus strains were isolated from raw fishes among 33 out of 64 (51.6%). Among 33 isolates, 16 isolates (48.5%) were resistant to ampicillin, 7 isolates (21.2%) were resistant to amikacin, and all isolates were not resist to other antibiotics such as amoxicillin & clavulanic acid, sulfamethoxazole & trimethopenem, ciprofloxacin, cefotaxime and cefepime. Although the prevalence of V. parahaemolyticus was high in raw fishes compared to other studies, antimicrobial resistance rate of the isolates was relatively low. These results could be useful information for risk assessment of V. parahaemolyticus in raw fishes.

Endocrine disruptors are exogenous chemicals that their endocrine disrupting effects mediated by androgenic signaling plays crucial roles in the control of development and several androgen-related diseases. However, there are no authorized in vitro screening and testing methods to evaluation of (anti-)androgenic activity. To find out a better in vitro cell line model, we have previously reported that 22Rv1 cells, a human prostate cancer cells contained functional Androgen Receptor (AR), might be an appropriate model for the evaluation of (anti-)androgenic endocrine disruptors. Based on this result, we developed a stable 22Rv1/mouse mammary tumor virus (MMTV) cell line to test AR-mediated transcriptional activation (TA). Using 22Rv1/MMTV cells, we established the test protocol and optimized the testing condition for AR-TA assay. In this study, we performed the inter-validation assay by four different laboratories to evaluate the 20 coded chemicals which were selected from the ICCVAM list (ICCVAM, 2003) or academic articles that exhibited exact (anti-) androgenic activity. The statistical analysis of the results of the inter-laboratory validation study revealed that there was reproducibility between the four participating laboratories. In conclusion, 22Rv1/MMTV AR-TA assay might be a quick and relatively inexpensive method, which can be used to screen large numbers of chemicals for their potential to activate or inhibit AR-mediated gene transcription. Furthermore, it will provide mechanistic data relevant to understanding adverse reactions observed in intact organisms.