본 연구는 Eucalyptus pulverulenta ‘Baby Blue’의 절 지에 있어 CoCl2, CuSO4, 8-HQS, BA, kinetin, TDZ, sucrose, glucose 그리고 fructose 등의 여러 가지 성분으 로 조성된 보존용액 처리가 절지수명, 생체중, 용액흡수 량 그리고 엽록소 함량에 미치는 효과를 구명하고자 수 행되었다. 보존용액에 첨가된 CoCl2, CuSO4, 8-HQS 그리고 BA에 있어 생체중 및 용액흡수량은 65mg • L−1 CoCl2 단용처리에서 가장 높게 나타났으며 BA 단용 또 는 혼용처리에서 생체중 및 용액흡수량은 낮게 나타나는 경향을 보였다. 절지수명 또한 증류수만을 사용한 대조구 와 함께 65mg • L−1 CoCl2에서 7.1일로 높게 나타났다. 유 의차는 없었지만 엽록소 함량은 80mg • L−1 CuSO4 처리 에서 높았다. BA, kinetin, TDZ 그리고 sucrose에 있어 절지수명은 1% sucrose에서 13.5일로 가장 길게 나타났 으며 생체중 및 용액흡수량도 다른 처리에 비해 높게 나 타났다. 엽록소 함량은 10mg • L−1 BA, 20mg • L−1 kinetin 에서 높은 경향을 보였으나 절지수명 연장에는 효과가 없 었다. 처리 농도에 따른 sucrose와 8-HQS의 단용 및 혼용 처리에 있어 3% sucrose + 8-HQS와 5% sucrose + 8-HQS 에서 높은 생체중을 보였고 용액흡수량은 1% sucrose + 8- HQS에서 높은 경향을 보였다. 절지수명은 1% sucrose 단 용 및 8-HQS와의 혼용처리에서 각각 11.8일과 11.2일로 높게 나타났다. Sucrose, glucose 그리고 fructose에 있어 생체중은 2%의 sucrose, glucose 그리고 fructose에서 높 았다. 절지수명은 sucrose 보다 1, 2% fructose 그리고 1% glucose에서 각각 15.7, 15.4, 15.1일로 가장 높은 것 으로 나타났다. 대체적으로 여러 종류의 당은 Eucalyptus pulverulenta ‘Baby Blue’의 절지수명을 연장시키는 것으 로 조사되었으며 그 중 glucose와 fructose는 절지수명 연 장에 sucrose보다 효과적인 것으로 나타났다.

본 연구는 정량적 미생물 위해평가(Quantitative microbial risk assessment: QMRA)에 절대적으로 필요한 9종의 식중독 세균, 2종의 바이러스, 1종의 원생동물에 대한 최소 감염량(minimum infective dose)을 선정한 연구이다. 주요 식 중독 미생물들의 최소 감염량을 선정하기 위하여, 1980년부터 2012년까지 PubMed, ScienceDirect database 등에서 주요 식중독 미생물들의 최소 감염량 및 위해평가 자료 82종을 수집하였다. 수집된 자료는 메타분석(mata-analysis) 에서 사용되고 있는 relative frequency(fi, 상대빈도 값)를 계 산하여 가장 적정한 최소 감염량을 추정 및 선정하였다. 주요 식중독 미생물들의 최소 감염량은, B. cereus 105 cells/g (fi = 0.32), C. jejuni 500 cells/g (fi = 0.57), Cl. perfringens 107 cells/g (fi = 0.56), Pathogenic E. coli 중 EHEC 10 cells/ g (fi = 0.47), ETEC 108 cells/g (fi = 0.71), EPEC 106 cells/g (fi = 0.70), EIEC 106 cells/g (fi = 0.60), L. monocytogenes 102~103 cells/g (fi = 0.23), Salmonella spp. 10 cells/g (fi = 0.30), Shigella spp. 100 cells/g (fi = 0.32), S. aureus 105 cells/g (fi = 0.45), V. parahaemolyticus 106 cells/g (fi = 0.64), Hepatitis A virus 10~102 particles/g (fi = 0.33), Noro virus 10 particles/g (fi = 0.71), C. pavum 10~102 oocyst/g (fi = 0.33)으로 나타났다. 본 연구결과는 향후 국내 QMRA를 통한 위해수준 추정결과의 정확성을 향상시키는데 기여할 수 있을 것으로 기대된다.

본 연구는 정량적 미생물 위해평가(Quantitative microbial risk assessment: QMRA)에 절대적으로 필요하지만 국내의 경우 관련 정보 및 자료가 부족한 주요 식중독 원인 미생물에 대한 용량-반응모델(dose-response models) 관련 자료를 수집·정리하여 가장 적합한 용량-반응 모델을 분석 및 선정하였다. 1980년부터 2012년까지 식중독 발생과 관련이 있는 26종의 세균, 9종의 바이러스, 8종의 원생동물 관련 용량-반응 모델 및 위해평가 자료들을 중심으로 국내 NDSL (National Digital Science Library), 국외 PubMed, ScienceDirect database에서 총 193개의 논문을 추출하여 정리하였다. 조사된 자료로부터 세균별, 바이러스별, 원생 동물별 용량-반응 모델의 미생물 위해평가 활용여부를 확인하고, 위해평가에 활용된 모델들을 메타분석(meta-analysis) 에서 사용되고 있는 Relative frequency (fi, 상대빈도 값) 를 계산하여 가장 적정한 용량-반응 모델을 제시하였다. 주요 식중독 원인 미생물들인 Campylobacter jejuni, pathogenic E. coli O157:H7 (EHEC / EPEC / ETEC), Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococcus aureus, Vibrio parahaemolyticus, Vibrio cholera, Rota virus, Cryptosporidium pavum의 적정 용량-반응 모델 은 beta-poisson (α = 0.15, β = 7.59, fi = 0.72), beta-poisson (α = 0.49, β = 1.81 × 105, fi = 0.67) / beta-poisson (α = 0.22, β = 8.70 × 103, fi = 0.40) / beta-poisson (α = 0.18, β = 8.60 × 107, fi = 0.60), exponential (r = 1.18 × 10−10, fi = 0.14), betapoisson (α = 0.11, β = 6,097, fi = 0.09), beta-poisson (α = 0.21, β = 1,120, fi = 0.15), exponential (r = 7.64 × 10−8, fi = 1.00), beta-poisson (α = 0.17, β = 1.18 × 105, fi = 1.00), betapoisson (α = 0.25, β = 16.2, fi = 0.57), exponential (r = 1.73 × 10−2, fi = 1.00), and exponential (r = 1.73 × 10−2, fi = 0.17) 로 각각 선정하였다. 본 연구에서 제시된 용량-반응 모델 들은 향후 국내 QMRA 관련 연구 및 진행에 많은 도움이 될 것으로 기대된다.

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.

In this study, the contamination levels of total aerobic bacteria, E. coli, total coliform and S. aureus of seasoned dried fishes (SDF) in Korea were investigated. A total of 81 SDF samples were purchased randomly from 28 stores. Contamination range of total aerobic bacteria, total coliform and S. aureus were 150~1,700,000, 10~31,000and 10~220 CFU/g, respectively. E. coli was detected in only one samples in the qualitative test. We have analyzed quantitatively Staphylococcal enterotoxins (SE-type A, C and D) produced by S. aureus contaminated in SDF using a TECRA kit and standard curve. The curve equation was Y = 0.1499 * X + 0.1183 and maximum amount of SEs in SDF was 0.71 ng/ml. Reduction speed of S. aureus in SDF stored at 37 ℃ was the highest among the samples stored for 8 days at different temperature of 7, 18 and 37℃ . On the basis of the results, SDF in Korea can be contaminated by a variety of pathogenic bacteria. Therefore, precautionary measures are necessary for consumer protection, including the improvement of sanitary conditions in the processing plants in Korea.

Predictive mathematical models were developed for predicting the kinetics of growth of Listeria monocytogenes in smoked salmon, which is the popular ready-to-eat foods in the world, as a function of temperature (4, 10, 20 and 30℃). At these storage temperature, the primary growth curve fit well (r² = 0.989~0.996) to a Gompertz equation to obtain specific growth rate (SGR) and lag time (LT). The Polynomial model for natural logarithm transformation of the SGR and LT as a function of temperature was obtained by nonlinear regression (Prism, version 4.0,GraphPad Software). Results indicate L. monocytogenes growth was affected by temperature mainly, and SGR model equation is 365.3-31.94*Temperature+0.6661*Temperature^2 and LT model equation is 0.1162-0.01674*Temperature+0.0009303*Temperature^2. As storage temperature decreased 30℃ to 4℃, SGR decreased and LT increased respectively. Polynomial model was identified as appropriate secondary model for SGR and LT on the basis of most statistical indices such as bias factor (1.01 by SGR, 1.55 by LT) and accuracy factor (1.03 by SGR, 1.58 by LT).

Risk ranking must be determined for various hazards/food combinations to conduct microbial risk management effectively. Risk Ranger is a simple, easy-to-use calculation tool developed in Microsoft Excel and designed to rank the risk (low, medium, and high) for semi-quantitative microbial risk assessment. The user is required to answer 11 questions in Risk Ranger related to 1) severity of the hazard, 2) likelihood of a disease-causing dose of the hazard being present in the meal, and 3) the probability of exposure to the hazard in a defined time. This study determined the risk ranking for twenty three combinations of foodborne pathogens/potentially hazardous foods (PHFs) using a Risk Ranger. In this study, pathogenic E. coli in fresh cut produce salad was scored as 79, which was the highest rank among the 23 combinations of the foodborne pathogens and PHFs. On the other hand, zero risk was obtained with V. parahaemolyticus in sushi, Salmonella in meat products and E. coli O157:H7 in hamburger patties. Although Risk Ranger is very simple method to rate the risk of foodborne pathogens and PHFs combination, the accuracy of result was mainly affected by the availability and accuracy of data in the literature. According to the result of literature review, the data are needed for contamination rate of raw materials, consumption amount/frequency of PHFs, and the effect of processing on pathogen. Risk ranking must be continuously revalidated with new data.

In this study, predictive mathematical models were developed to predict the kinetics of Listeria monocytogenes growth in the mixed fresh-cut vegetables, which is the most popular ready-to-eat food in the world, as a function of temperature (4, 10, 20 and 30oC). At the specified storage temperatures, the primary growth curve fit well (r2 = 0.916~0.981) with a Gompertz and Baranyi equation to determine the specific growth rate (SGR). The Polynomial model for natural logarithm transformation of the SGR as a function of temperature was obtained by nonlinear regression (Prism, version 4.0, GraphPad Software). As the storage temperature decreased from 30oC to 4oC, the SGR decreased, respectively. Polynomial model was identified as appropriate secondary model for SGR on the basis of most statistical indices such as mean square error (MSE = 0.002718 by Gompertz, 0.055186 by Baranyi), bias factor (Bf = 1.050084 by Gompertz, 1.931472 by Baranyi) and accuracy factor (Af = 1.160767 by Gompertz, 2.137181 by Baranyi). Results indicate L. monocytogenes growth was affected by temperature mainly, and equation was developed by Gompertz model (−0.1606 + 0.0574*Temp + 0.0009*Temp*Temp) was more effective than equation was developed by Baranyi model (0.3502 − 0.0496*Temp + 0.0022*Temp* Temp) for specific growth rate prediction of L. monocytogenes in the mixed fresh-cut vegetables.

This research was conducted to assess applicability of photostimulated luminescence (PSL) and Thermoluminescence (TL) methods for investigation of infant and young children products, nut, seasoned dried fish,spice, dried fruits, fruit & vegetable, grain and marine products, which are not approved for irradiation in Korea. PSL results show that the photon counts of non-irradiated samples were lower than 700, while those of irradiated samples were higher than 700. In TL measurement, TL ratio of irradiated samples were higher than 0.1 or ones can decrease below 0.1 whereas the temperature range of TL Glow curve was between 150-250℃. Monitoring result about 8 class of 325 not approved to irradiated foods, photon counts of samples were less than 700, and after re-irradiation TL Ratio (TL₁/TL₂) through re-irradiation step at 1 kGy were higher than 0.1 for the all samples. Therefore, these results suggested that PSL and TL measurements were useful detection methods for 8 class food products not approved to irradiation in Korea and all sample (325 cases) were not irradiated when we analysed by PSL and TL methods.

This research was conducted to know application of Photostimulated luminescence (PSL) and Thermoluminescence (TL) methods by irradiation dose for leaching tea, sauces and starch approved in Korea. Leaching tea, sauces and starch powder were treated with 60Co gamma ray at dose 0~10 kGy for detection trial whether they are irradiated or not by measuring PSL and TL for whole samples. PSL values were less than threshold value 700 and were negative for non-irradiated samples but more than 5,000 and were positive for irradiated ones. PSL results of leaching tea and sauces showed the correct identification for non-irradiated and irradiated samples, respectively except starch samples. To enhance the reliability of the TL result, the first glow curve (TL1) was compared with the second glove curve (TL2) obtained after a re-irradiation step at 1 kGy. The TL ratio (TL₁/TL₂) was in good agreement with the reported TL threshold for both the non-irradiated (< 0.1) and irradiated (> 0.1) samples. TL results of leaching tea, sauces, starch showed the correct identification for non-irradiated and irradiated samples, respectively. This study was performed to know application of PSL and TL methods for leaching tea, sauces and starch, and the methods were able to detect the irradiation products.

유전자재조합식품과 관련된 담당 총무원 및 기타 전문가들의 인지도출 조사하기 위해서 설문조사를 실시하였다. 응답자들을 근무년수별, 소속별, 업무별로 분류하였으며 설문지의 각 문항에 대한 결과는 위 분류별로 통계분석하여 빈도수 및 응답률로 나타내었다. 조사 결과, 유전자재조차식품에 대해 들어본 경험은 95% 이상으로 나타났으며, 유전자재조합식품의 혜택은 식량난 해결이라고 가장 만이 응답하였다. 유선자재조합식품의 표시에 대해서는 '90% 이상이 표시해야 한다' 또는 '가급적 표시해야 한다'로 응답하석 식품위생공무원 및 기타 전문가들은 유전자재조합 표시를 절실히 필요로 하고 있었으며 학력 수준 및 전문 수준이 높을수록 구입하여 먹을 의향이 높은 것으로 나타났다. 응답자 대부분은 근무년수별, 소속별, 업무별 구분에 상관없이 기본적인 지식은 있는 것으로 나타났으나 시·도 공무원 및 국립검역소 그룹은 다른 전문가 그룹에 비해서 유선자재조합식품에 대한 정보가 부족한 깃으로 나타났다. 유전자재조합식품에 대한 안전성 인식은 대제로 안전하다는 견해를 가지고 있었으나 20년 이상 근무자와 일반 행정 업무자는 다른 그룹에 비매시 안신하지 않거나 불안하다는 견해를 더 많이 나타냈다 식품의 안전성을 위협하는 가장 큰 요인은 ‘식품취급 부주의 및 취급 불량'으로 응답하였으며, 유전자재조합식품이 위협요인이라고 응답한 사람은 매우 적었나(4.4%). 결론적으로 유전자재조합식품 관련 공무원 및 기타 전문가들은 일반시민들에 비해서 섭취나 안전성에 보다 긍정적인 견해를 나타냈지만 생물학 지식에 대해서는 그룹별 차이가 있었으며 유전자재조한식품에 대한 민인업무 치리에 어려운 점을 겪고 있는 것으로 보아 관련 전문가들에게도 교육 및 홍보가 필요한 것으로 파악되었다

전국 4개 대도시(서울, 부산, 대전, 광주)를 중심으로 시중에서 유통되는 김밥 중 황색포도상구균의 오염도 자료와 환경조건별 미생물 변화를 예측하는 Food MicroModel^R을 활용하여 김밥 중 황색포도상구균으로 인해 식중독이 발생하지 않을 유효기간을 산정하였다. 분식점(n=79), 백화점(n=10), 편의점(n=20)으로 구분하여 분석한 여름철 평균 황색포도상구균 모니터링자료(검출률 각각 39.2%, 30%, 15%)를 시중에서 유통되는 김밥 중 황색포도상구균의 최대 섭취유효시간 산정에 활용하였으며, 모델 운영 시 김밥 중 황색포도상구균으로부터 enterotoxin이 생성되는 균수인 2×^7에 도달하는데 ℃~ 요되는 시간을 최대섭취유효시간으로 추정하였다. 하절기의 환경조건을 고려하기 위하여 ℃ 온도 조건하에서, pH, NaCl %, aw 0.99의 조건을 적용하였다. 추정된 최대섭취유효시간은 일반적인 성인이 김밥 1인분(171 g)을 섭취하는 것을 기준으로 하였을 때 구입 이후 28~30℃에서 방치할 경우 분식점은 3.9~4.6시간, 백화점 6.7~7.9시간, 편의점은 7.4~8.7시간이었다. 또한 구매한 김밥이 황색포도상구균에 기인한 식중독으로부터 안전할 최대섭취 유효시간은 99% 안전 확률에서 여름철 분식점 자료를 근거하여 30℃에서 1.9시간이었으며 15℃인 경우는 17.7시간이었다.