The aim of this study was to evaluate the TEMPOⓇ STA automated most probable number (MPN) system for the enumeration of Staphylococcus aureus (S. aureus) in comparison with a standard culture method. Artificially inoculated food products with S. aureus - triangle kimbap, sliced spring onion, dried filefish fillet, danpatjuk (sweet red-bean porridge with small rice dumplings)- were tested in this study. Twenty-five grams of each of food samples were added into 225 ㎖ of sterilized phosphate buffered saline in a TEMPOⓇ stomacher bag followed by stomaching for 2 min. One milliliter of the stomached sample was added to a bottle of culture medium. Cards were filled and sealed in the automated filler and then were incubated for 24 h at 37℃. After incubation, the cards were placed in the automated TEMPOⓇ reader and MPN results were generated. For comparison with a culture method, decimal dilutions were prepared from the same homogenized samples described above, transferred onto Baird Parker and Baird Parker-Rabbit Plasma Fibrinogen (BP-RPF) agar plates, and then incubated at 37℃ for 24 h. The performance of TEMPOⓇ STA method is equivalent to the culture method using Baird Parker or BP-RPF agar count plate for the enumeration of S. aureus in foods, eliminating a time-consuming and laborious process.

Real-time PCR could help to provide answers to urgent questions about the incidence, prevalence, and epidemiology of currently emerging food-borne bacteria and diseases as identification and detection tools. The objective of this study was carried out to examine several critical parameters that must be optimized when converting from the ABI Prism 7000 SDS platform to the Cepheid SmartCycler Ⅱ so as to directly use the same primer and probe sequences. A lyophilized master mix-OmniMix HS bead, MgCl2 concentration, and PCR cycling conditions were evaluated so as to convert to a new platform, Smartcycler Ⅱ. The best optimal cycling conditions to detect Cronobacter sakazakii on SmartCycler Ⅱ were as follow: initial denaturation at 95℃ for 2 min followed by 45 cycles of 95℃ for 15 s, and 60℃ for 60 s using OmniMix HS bead contained 6 mM MgCl2 concentration. And the Ct value was 16.97 compared to 23.84 of Ct value in ABI Prism 7000 SDS. This result showed that when the several analytical parameters were taken the consideration for optimization, it could be performed assays between real-time PCR platforms. Also it is need of further study to develop the new single multiplex real-time PCR method for determining various Cronobacter spp. including three subspecies, too.

This study was carried out to evaluate the microbiological characteristics of retail chicken meats stored under various conditions. Nine of whole chickens and nine of chicken breasts were used for bacterial analysis. Each chicken meat was divided into subsamples of 25 g each followed by storage at room temperature (25℃), refrigeration temperature (4 ℃), and freezing temperature (—20℃) for 180 min, 5 days, and 3 days, respectively. The standard plate counts were performed for the enumeration of the total aerobic bacteria. The number of aerobic bacteria was gradually increased by 1 log in samples held at the room temperature for 180 min. There was statistical difference in the number of bacteria between at 0 min and at 180 min of storage. For samples stored at 4℃ for 5 days, the number of bacteria was increased from 5.11 to 7.26 log CFU/g in chicken breast and 3.83 to 6.04 log CFU/g in whole chicken with statistical difference. No significant changes were observed in frozen chicken. The results of this study may provide useful information to consumers for proper storage and safe handling of chicken meats.

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.

단축 압출 성형기를 이용하여 쌀을 원료로 한 스낵을 제조하기 위하여, 반응 표면 분석 방법(response surface methodology : RSM)을 도입하여 제조 조건의 최적화를 시도하였다. 수분함량, 스크류 회전속도, 배럴의 온도를 변수로 하여 전단강도, 팽화율, 수분 용해도 지수, 수분흡수지수, 호화도 등의 결과를 RSM 컴퓨터 프로그램에 입력하여 contour map을 적성하여 분석하였다. 쌀 압출 성형물의 최적 제조조건은 수분함량 17%, 배럴의 온도 125℃, 스크류 회전속도 210rpm으로 추정되었다.

단백질 가수분해물의 항산화 작용을 해명하기 위하여 고등어 근육단백질을 이용하여 복합효소, alcalase, bromelain, pancrease, pepsin, α-chymotrypsin, trypsin 및 papain으로 가수분해시키고 linoleic acid와의 모델반응을 통하여 이들 가수분해물의 항산화능과 α-tocopherol과의 상승작용 및 아미노산 조성, Bio-gel P-2 column에 의한 활성획분의 분리 및 획분별 항산호능과 금속이온 봉쇄작용 등을 살펴본 결과, 8가지 효소에 의한 고등어 근육단백질 가수분해물의 항산화능은 우수한 것으로 나타났으며, 특히 복합효소, bromelain 및 alcalase에 의한 가수분해물의 항산화능이 다른 효소에 의한 경우에 비하여 다소 우수한 것으로 나타났다. 이들의 α-tocopherol과의 상승작용 및 금속이온(Fe^3+, Cu^2+)에 의한 산화촉진 억제효과 또한 우수한 것으로 나타났으며, 아미노산의 조성은 전반적으로 aspartic acid, glutamic acid 및 lysine의 함량이 높은 것으로 나타났다. Bio-gel P-2 column에 의한 활성획분의 분리 결과, 복합효소 유래 가수분해물의 경우는 part E. bromelain 유래 가수분해물의 경우는 part e에서 항산화능이 큰 것으로 나타났으며, 이들의 분자량은 1, 400보다 적을 것으로 추정되었다. 또한 획분별 금속이온 봉쇄작용은 항산화 획분인 part E에서 큰 것으로 나타났으며 획분별 항산화능과 밀접한 관련이 있는 것으로 나타났다. 이들 활성획분의 아미노산 조성은 part E의 경우는 histidine, arginine, phenylalanine 및 lysine이, part e의 경우는 lysine, glutamic acid 및 leucine의 함량이 높은 것으로 나타났다.

In the present study, an attempt was made to investigate the effect of stearic acid on the autoxidation of the commercial rice bran oil. Rice bran oil samples with stearic acid at 0.1, 0.3 and 0.5% level were kept at 45±0.3℃ for 40 days. The rate of autoxidation of each samples was estimated regulary on the basis of the changes of peroxide value, acid value, anisidine value and the fatty acid composition. The results were as follows : The peroxide, acid and anisidine values of the rice bran oil with the stearic acid at 0.1, 0.3 and 0.5% levels during the autoxidation increased as compared with that of the rice bran oil without the stearic acid. The induction period of the rice bran oil without the stearic acid, control was 19.8 days, while those of the bran oil with stearic acid at 0.1, 0.3 and 0.5% levels varied 19.0 days, 17.7 days and 14.2 days, respctively. In conclusion, it seemed that stearic acid acted as weak prooxidant when added at 0.1, 0.3 and 0.5% levels to the commercial rice bran oil. The prooxidant activity of the stearic acid appeared to depend on the oxidative mechanism and their concentration.