The purpose of this study was to evaluate microbiological contamination of knives and cutting boards in child-care centers. Materials used in this study were swabbed of cutting boards and knives (blade, handle of knife, and joint of handle and blade) in 129 child-care centers. Mean values of total aerobic bacteria of swabs of knives and cutting boards were 1.7±0.7 log cfu/100 cm2 and 1.7±0.9 log cfu/100 cm2, respectively. Contamination levels of coliform bacteria from knives and cutting boards were 1.5±0.6 log cfu/100 cm2 and 1.7±0.8 log cfu/100 cm2, respectively. Comparing microbiological contamination levels of knives and cutting boards according to type and size of child-care centers, there was no significant difference. Bacillus cereus was detected in knife handles and cutting boards. Diarrhea-type toxin gene (entFM) was detected in B. cereus isolates. Antibiotic resistance tests showed that B. cereus was resistant to β-lactam antibiotics. To reduce microbiological contamination levels of knives and cutting boards in child-care centers and prevent food poisoning from bacteria contamination, continuous education by children's food-service management center is needed for sterilization and disinfection of knives and cutting boards.

2019년 경기도내 전통시장, 대형마트, 반찬전문점에서 수거한 반찬류의 미생물 품질을 조사하였다. 반찬류 108 건의 식중독 원인균을 검사하였고, 그 중 75건에 대해서는 구매 장소별, 조리 방법별 위생세균 검사를 진행하였 다. 14건(12.9%)에서 Bacillus cereus가 검출되었으며, 나머지 94건에서는 식중독 원인균이 검출되지 않았다. 위생 세균 검사에서 일반세균의 평균 검출량(범위)은 전통시장이 5.8 log CFU/g (3.0-8.2 log CFU/g), 대형마트는 4.3 log CFU/g(2.3-7.8 log CFU/g), 반찬전문점에서는 3.8 log CFU/g (0.0- 6.9 log CFU/g)로 나타났으며, 구입 장소에 따른 유의적인 차이가 있었다(Ρ <0.05). 전통시장의 일반세균수와 대장균 군은 대형마트, 반찬점과 통계적으로 유의한 차이가 있었고, 생채류, 나물류, 볶음류, 젓갈류, 조림류 순으로 일반 세균수와 대장균군이 높게 검출되었다. 콩나물 무침의 보 관온도별 일반세균수의 변화는 냉장보관(4oC)에서는 72시간 경과에서도 큰 변화가 없었으나, 상온보관(20oC) 및 고 온보관(35oC) 시 구입 후 각각 9시간, 6시간 경과 시 부패의 가능성이 제기되어 구입 즉시 냉장보관 할 것을 권장하며, 제품을 판매하는 시설에서도 냉장보관을 하여야 할 것이다.

본 연구에서는 어린이집 급식실 실내공기와 급식테이블 및 조리종사자 손의 미생물학적 안전성을 평가하고자 하였다. 본 실험에서 사용된 재료는 어린이집 조리 종사자 24명의 손과 어린이집 18곳의 급식테이블 및 93곳의 실내공기를 실험대상으로 하였다. 조리 종사자 손의 미생물 채취는 Glove juice법, 급식테이블의 표면 미생물 채취는 Swab 법에 따라 채취하였다. 어린이집 실내공기의 미생물 오염도는 자연 방치법에 따라 실험하였다. 조리 종사자 손의 일반세균 오염도는 평균 5.8±1.9 log CFU/hand로 나타났고, 대장균군 오염도는 평균 4.0±2.4 log CFU/hand로 나타났다. 급식테이블의 일반세균 오염도는 평균 4.3±3.0 log CFU/100 cm2 로 나타났고, 대장균군 오염도는 평균 2.6±3.3 log CFU/ 100 cm2로 나타났다. 어린이집 조리 종사자 손과 급식테이 블에서 B. cereus가 각각 2건씩 검출되었다. 실내공기 중 일반세균수 오염도는 평균 28±7.2 CFU/plate, 대장균군 오염도는 평균 3.1±2.9 CFU/plate로 나타났다. 또한, 실내공기 중 B. cereus 오염도는 평균 1.7±0.2 CFU/plate, S. aureus 오염도는 평균 1.6±0.5 CFU/plate로 나타났다. 이러한 결과를 종합해 볼 때, 어린이집 급식테이블 표면에 존재하는 미생물 오염도를 감소시키기 위한 식사 전 소독이 필요한 것으로 판단되었다. 또한, 실내공기 중 미생물 오염도 저감화를 위해 주기적인 환기와 급식 관계자들의 위생모, 마스크 및 위생복 등의 청결관리가 필요한 것으로 판단되었다.

본 연구는 빙과류의 종류별로 미생물학적 안전성 평가를 수행하기 위하여 시중에 판매되고 있는 아이스크림의 종류별로 일반세균수를 측정하였다. 또한 냉동저장 중 아이스크림에서 미생물의 생존가능성을 확인하기 위하여 저장온도를 달리하여 S. aureus, B. cereus, L. monocytogenes 와 E. coli를 빙과류의 종류별로 각각 접종하여 저장기간에 따라 생균수를 측정하였다. 시판중인 빙과류 중 빙과 2제품과 비유지방아이스크림 1제품에서는 10 CFU/mL 이하 로 검출되었으며, 이외의 빙과류 제품에서는 1.04-2.10 log CFU/mL이 검출되었다. 측정한 16종의 빙과류 모두 식품공 전상의 세균수 기준 이하로 측정되어 빙과류에서의 미생물 오염수준이 낮은 것으로 나타났다. 빙과류에 미생물을 접종 하여 각각 -5oC, -10oC, -18oC에 저장하여 주기적으로 생균 수를 측정한 결과 저장기간에 따라 모두 감소하는 경향을 나타내었다. 모든 저장조건에서 생균수가 감소하였으며 냉동저장 중에서는 온도가 높을수록 더 많은 미생물이 사멸하였다. 특히, 빙과제품에서는 -5oC에서 모든 균이 1~4주 이 내에 사멸하였는데 이는 빙과제품의 낮은 pH와 접종 후 냉동조건에서 생긴 빙결정들에 의한 것으로 사료된다. 냉동조건에서 미생물은 증식하지 않았으며 효소의 반응 또한 냉동온도에서는 매우 천천히 일어나기 때문에 맛의 변화는 장기간 저장해도 잘 일어나지 않을 것으로 사료된다. 따라서 빙과류의 유통기한에 있어서 저장 및 유통 온도가 잘 지켜진다면 미생물학적 안전성은 확보가 될 것으로 사료되며, 품질변화 중 조직감의 변화를 고려해야 한다. 빙과류의 유통기한에 관한 연구를 위해서 미생물학적 안전성뿐만 아니 라 유통 및 저장 중 온도변화에 따른 빙결정 생성과 같은 조직감의 변화와 지방산패 등 이화학적 분석을 포함한 추가적인 연구가 필요할 것으로 사료된다.

Recently there is a growing interest in the airborne spread of virus. In particular, there is growing interest in secondary infection through the air in the hospital. The distribution of air-born virus depends on ventilation system installed in a hospital. In this study, simulations were carried out to predict the move of air-born virus by ventilation system at hospital. Simulation results showed that pressure distribution was –372.05Pa ∼ -3.45 Pa at 1st floor incase of only used mechanical exhaust at bathroom, shower stall , storage, kitchen etc.. if ventilation switch from used mechanical exhaust to mechanical exhaust & mechanical supply. Simulation results showed that pressure distribution was -336.44Pa at stair hall < -0.2Pa at bathroom < mean 1.19Pa at other room. So simulation results showed that using all of the mechanical supply and mechanical exhaust was more effective then the mechanical exhaust for maintain the pressure distribution in hospital. It was also showed that when using the mechanical supply and mechanical exhaust more effectively prevention of air born virus diffusion.

Foodborne disease outbreaks associated with produces have been increasing in occurrence worldwide. This study investigated microbial contamination levels on thirteen kinds of agricultural products from farms stage to evaluate potential hazards associated with foodborne illness. A total of 1,820 samples were collected in major cultivating area from 2013 through 2015, and analyzed to enumerate aerobic bacterial counts, coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study for four kinds of microorganisms (Escherichia coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.01 to 7.18 log CFU/g, with the highest bacterial cell counts recorded for watermelon. Coliforms were detected in 651 samples (35.8%) with a minimum of 0.01 log CFU/g and a maximum of more than 5 log CFU/g. B. cereus was detected in 169 samples (9.3%) ranging from < 0.01 to 2.48 log CFU/g among total samples analyzed. S. aureus was detected in 14 samples (0.7%) with a minimum of 0.01 log CFU/g and a maximum of 1.69 log CFU/g. E. coli was detected in 101 samples (5.5%) among 1,820 samples. E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in any of the samples. The microbial contamination levels of several agricultural products determined in this study may be used as the fundamental data for microbiological risk assessment (MRA).

Effects of dielectric barrier discharge atmospheric cold plasma (DACP) treatment on the inhibition of Salmonella and the storability of grape tomato were investigated. Grape tomatoes, with or without inoculation with a cocktail of three strains of Salmonella (~8 log CFU/g tomato), were packaged in a polyethylene terephthalate commercial clamshell container and cold plasma-treated at 35 kVat 1.1 kHz for 3 min using an DACP treatment system equipped with a pin-type high-voltage electrode. DACP treatment resulted in ~1 log CFU/tomato reduction of Salmonella, irrespectively of the size of container (316, 595vs. 758 cm3), the number of grape tomatoes in the container (3, 7, vs. 11), and the position of the tomato in the container(P > 0.05).Rolling integrated during treatment significantly increased the Salmonella reduction rates to 3.1±0.3 and 3.3±0.8 log CFU/tomato in the single-layer and double-layer configurations of the tomato samples in the container (992 cm3), respectively. Rolling-adopted DACP initially reduced the number of total mesophilic aerobes and yeast and molds in the double layer configuration of tomato samples by 1.3±0.3 and 1.5±0.2 log CFU/tomato, respectively, without altering the color and firmness of the tomatoes. The growth of Salmonella, total aerobes, and yeast and molds on DACP-treated grape tomatoes was effectively prevented during storage at 10 °C. DACP treatment did not influence the tomato color index (a*/b*), firmness, weight loss, pH, total soluble solid content, and lycopene concentration of grape tomatoes at 10 and 25 °C (P> 0.05). DACP treatment holds promise as a post-packaging process for improving microbial safety against Salmonella and storability of fresh grape tomatoes.

이 연구는 패류가 다량으로 양식되고 있는 남해안 일부해역 해수의 세균학적 위생안전성을 평가하기 위하여 조사해역 내에 영향을 줄 수 있다고 판단되는 해수 14곳을 선정하여 2014년 3월부터 10월까지 총 6차례 조사를 실시하였으며 그 결과는 다음과 같다. 해수는 수온이 평균 21.2℃, 염분농도는 32.43‰, pH는 7.92, 용존산소는 7.83 mg/L으로 조사되어 우리나라 수질환경기준으로 볼 때 1등급으로 조사되었다. 전도도는 44,600 us/cm, 탁도는 1.93 NTU로 조사되었다. 남해안 일부 조사해역 해수의 위생학적 안전성을 조사한 결과 대장균군은 평균 < 1.8~790 MPN/100 mL, 90번째값이 168.1 MPN/100 mL, 기하학적 평균이 12.8 MPN/100 mL으로 나타났고, 분변계대장균은 < 1.8~790 MPN/100 mL,90번째 값이 50.5 MPN/100 mL, 기하학적 평균값이 6.5 MPN/100 mL로 조사되어 정착성 수산물 생산해역 위생관리기준 중 청정해역의 기하학적 평균 기준치인 14 MPN/100 mL를 넘지 않아 청정해역으로 나타났다. 그러나 5월과 7월에 43 MPN/100 mL를 초과하는 시료가 35.7%와 28.6%로 KSSP 기준치인 10%를 초과하여 계절에 따라서 다소 차이가 있는 것으로 나타났다. 조사해역은 폐쇄성 내만으로 적은 오염원에도 크게 영향을 받을 수 있으므로계절에 따라서 철저한 해역의 관리가 요구되었다.

본 연구는 국내산 곶감의 미생물 및 aflatoxin에 대한 안전성을 평가하여 곶감의 안전관리의 기초자료로 활용하고자 수행하였다. 본 연구를 위하여 반건시 34농가, 건시 61 농가, 감말랭이 10 농가에서 수집하여 수분활성도와 당도, 위생지표세균 (일반세균수, 대장균군, E. coli)과 병원성미생물(Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus), aflatoxin을 조사하였다. 감말랭이, 건시, 반건시의 수분활 성도는 각각 0.81, 0.86, 0.91 였으며 당도는 감말랭이 54.9%, 건시 49.5%, 반건시 40.5%로 당도와 수분활성도는 반비례 하였다. 곶감의 일반세균수는 감말랭이 3.93 ± 0.96 log CFU/g, 건시 2.12 ± 0.93 log CFU/g, 반건시 1.50 ± 1.08 log CFU/g로 감말랭이의 오염도가 가장 높았다. 또한 S. aureus는 감말랭이 40.0%, 건시 29.5%, 반건시 23.5%의 시료에서 검출되었고, E. coli는 건시 6.6%, 반건시 2.9% 의 시료에서 검출되었다. B. cereus는 건시 39.3%, 반건시 20.6%의 시료에서 검출되었고 검출 수준은 0.7~2.3 log CFU/ g이었다. Aflatoxin의 경우는 ELISA법으로 분석했을 때 감 말랭이, 건시, 반건시에서 각각 30%, 4.9%, 2.9%가 검출 되었고 검출농도는 1.0~1.1 ppb 이었다. ELISA법에서 양 성시료를 대상으로 UPLC로 재분석한 결과 aflatoxin은 검 출되지 않았다. 본 연구의 결과로 미루어 볼 때 안전한 곶 감 생산을 위한 위생관리기술의 개발과 곶감생산 농가의 지속적인 위생교육이 필요하다고 사료된다.

The recent rise in SARS and bird flu infections around the world has raised the interest in studying the habits of air borne pathogens such as germs and viruses. In this study, simulations were carried out to predict the performance of UVGI air sterilizer at preventing airborne infections inside a car, based on the installation position and the removing effect of the UVGI air sterilizer. Simulation results showed that the UVGI air sterilizer was most effective when located at the rear side of the front seats. It was also showed that when the out-air mode and the UVGI air sterilizer were set to the highest capacity, the microbial safety levels were maintained in a car for 21 hours.

본 연구는 기후변화와 관련하여 미생물학적 식품안전상쉽게 영향 받을 수 있는 식품과 관련 식중독세균을 결정하는데 이용할 수 있는 Risk Ranger를 활용한 Excel spreadsheet상의 모델을 개발하였고, 모델 입력값은 자료의 부족으로전문가 설문을 통해 결정하였으며, 확률분포모델과 @RISK를 이용한 시뮬레이션을 통해 실제 국내 식품중 기후변화에 대한 민감할 것으로 예상되는 상위 5개 식품군과 이들식품과 관련된 주요 식중독 원인균을 결정하였다. 추정결과, 상위 5종 식품과 관련 식중독 세균으로는 즉석섭취식품류(RTE) (황색포도상구균, 살모넬라, 병원성대장균 O157:H7)가 가장 큰 영향을 받을 것으로 나타났으며, 다음이 떡류 및 빵류 (황색포도상구균, 바실러스 세레우스), 식육 및알가공품 (살모넬라, 병원성대장균 O157:H7, 황색포도상구균), 두부류 또는 묵류 (바실러스 세레우스, 병원성대장균O157:H7, 황색포도상구균)였으며, 마지막으로 어육가공품(황색포도상구균, 비브리오, 병원성대장균 O157:H7)의 순으로 나타났다.

The transmission of the world Installed in an Office occurs through the air. Preventing that transmission, especially in indoor environments like those in airplanes, schools and offices, is a major public health concern. in this study the real situation of lab which is consist of dilution, Ultraviolet-C based air sterilization system. This model include indoor microbe transport which is generated human source. a computer simulation was performed to determine if such simulation can be used effectively to predict the more accurate, but difficult to perform, actual physical experiment. Result show that CFD can be modeled microbe transport effectively and it can be visualized microbe transport separation from flow streamline. also it make a good prediction of microbe transport.

In this study the real situation of apartment house in seoul is reproduced with multi-zone modeling program contam2.4. This model include immune building system(disinfection system) which is consist of dilution, Filter Technology and UVGI(ultra violet germicidal irrdiation). In this study experiments design method used for estimating interaction of HRV air change rate, UVGI air change rate and UVGI grade. Result show that HRV air change rate and UVGI air change rate is most influence factor for remove rate. also Interaction of HRV air change rate and UVGI air change rate is ost influence factor for remove rate.

Produce, including leafy vegetables, has been implicated in several outbreaks of food illness. To evaluate microbiological safety of lettuce and it’s cultivation area, a total of 147 samples were collected from lettuce farms and post harvest facility at Icheon, Gyeonggi province. The collected samples were assessed for presence of sanitary indicator microorganisms (Aerobic plate count, coliform count, Escherichia coli) and foodborne pathogens (Escherichia coli O157:H7, Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus). The population of APC was over 4.0 log CFU from most of the samples. While the numbers of APC, and coliform of lettuce at 62 days after transplanting were 4.18 log CFU/g, and 1.00 log CFU/g, respectively, those of 10 days after transplanting were 5.37 log CFU/g, and 2.87 log CFU/g, respectively. B. cereus was highly detected from soil and balance which were contaminated with 3.5 log CFU/g, and 2.6 log CFU/100 cm2, respectively. The number of E. coli recovered from gloves was 3.5 log CFU/hand. However, E. coli O157:H7, Salmonella spp., and L. monocytogenes were not detected. These data suggested that risk management system should be introduced to lettuce farms to enhance safety of lettuce.

The objectives of this study were to investigate the microbial contamination levels on food service in university and to provide the information of microbial contamination to improve food safety. A total of 288 samples were collected during summer and winter season between 2006 and 2008 from 4 food services located in the university in Western Gyeongnam and were used to detect sanitary indicator bacteria [aerobic plate count (APC), coliform,and Escherichia coli] and pathogenic bacteria (Staphylococcus aureus, Salmonella spp.). As a result, APC and coliform for hand and kitchen utensils which are used often by the employee were detected at high levels of 1.1~5.5and 1.3~5.3 log CFU/(100 cm2, hand), respectively. The contamination levels of APC and coliform in cooked foods and drinking water were 0.8~6.4 and 1.3~5.0 log CFU/(g, mL), respectively. Especially, the cooked foods showed the highest contamination for APC (2.1~6.4 log CFU/g) and coliform (1.0~5.0 log CFU/g). We think the reason that the cooked foods may be contaminated with APC and coliform on cooking process by using employee’s hand and kitchen utensils. Moreover, S. aureus for hand and kitchen utensils was detected at levels of 2.8~3.0 and 2.0~2.3 log CFU/(g,hand), but Salmonella spp. was not detected. According to the above results, contamination levels of the samples were mostly decreased irrespective of summer and winter season. The results obtained indicated that it is necessary to periodic monitoring for microorganism contamination and education about personal and environmental hygiene to employee for ensuring food safety of food service in university.

The purpose of this study was to investigate the antibacterial effect of films on shelf-life and microbiological Safety of pork meat. Effects of antimicrobial films against total aerobic bacteria, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus in pork meat were evaluated during storage of 14 days at 5℃, 10℃ and 15℃. Antimicrobial films were developed with addition of a natural substance, wasabi extracts (Wasabia japonica). At 5℃ storage, growth of total aerobic bacteria, E. coli O157:H7, L. monocytogenes were inhibited higher than at 10 and 15℃. Especially, the numbers of S. Typhimurium and S. aureus were increased gradually at 5℃ even in the control sample, and it takes more than 14 days to increase in every sample upto 6 log10 cfu/g. The higher antimicrobial effects of the films were observed at storage of 5℃ than at 10oC and 15℃. There was a limit of a single treatment of antimicrobial film to prolong shelf-life of pork meat. The synergistic effect of antimicrobial film were observed with addition of refrigeration at 5℃.

This study researched microbial change of quality according to the various phases of product flow of cooked pea and rice, cold cucumber and seaweed soup, soybean sprouts japchae feeding urban type of a commissary school and a satellite school in Daejeon area, also it suggested the possibility that the central commissary foodservice system can be established and utilized more developmental to identify its food of variation of temperature and state of safety unitl 3 hours after cooking for the case of delay of distribution and holding because of the satellite school of geographical location and traffic problem. The critical Control Points identified for each category of menu items were: Boiled pea and rice: inadequate distribution, holding and storing before assembly; Cold cucumber and seaweed soup: pre-preparation and post-preparation after cooking; Soybean sprouts japchae: Pre-preparation, post-preparation and storing. As the result of observation of the variation of temperature and microbial safety according to the delay of distribution and holding for each food, all of them were relatively safe until 3 hours after cooking, but cold cucumber and seaweed soup being stored for 3 hours, the value of E. coli is 103 CFU/g. The variation of temperature was more extreme in soybean sprouts japchae than cooked pea and rice and cold cucumber and seaweed soup. It was proved that the stainless container was excellent and that adequate holding container should be used.