This paper conducted a comparative analysis of the shear buckling characteristics of trapezoidal and sinusoidal corrugated steel plates considering of their initial imperfection. Initial imperfection refers to the state where the shape of the corrugated plate is initially not perfect. As such, an initially imperfect shape was assumed using the eigen buckling mode. To calculate the buckling stress of corrugated steel plates, the linear buckling analysis used a boundary condition which was applied to the plate buckling analysis. For the comparison of trapezoidal and sinusoidal corrugation, the shape parameters were assumed using the case where the length and slope of each corrugation were the same, and the initial imperfection was considered to be from 0.1% to 5% based on the length of the steel plate. Here, for the buckling analysis, ANSYS, a commercial FEA program, was used. From the results of buckling analysis, the effect of overall initial imperfection showed that the larger the initial imperfection, the lower the buckling stress. However, in the very thin model, interaction or local buckling was dominant in the perfect shape, and in this case, the buckling stress did not decrease. Besides, the sinusoidal model showed higher buckling stress than the trapezoidal one, and the two corrugation shapes decreased in a similar way.

The purpose of the study was to simplify standard HACCP manual for improving the on-site applicability and increasing the implementation rate of HACCP program for small- and medium-sized dairy farms (SMDF). A survey was carried out in 32 SMDFs using a structured questionnaire. The results indicated that the number of workers had a positive correlation with HACCP certifications (p < 0.05). Most of HACCP non-certified farms (66.7%) were run by two workers with 40-60 cows and milking yields of 1,000-1,500 L per day. Major drawbacks for dairy farmers to implement current HACCP system were the difficulties in daily recording and facility management (40%). On the basis of the survey results, it was suggested that the development of on-site standard HACCP manual and user-friendly record chart with O/X checklist were the most urgent factors to increase HACCP implementation rate. In addition, the alternative third party service for microbial and chemical tests could also be accompanied for small-sized dairy farms.

두 종류의 Cronobacter 선택배지(DFI agar, R&F agar) 의 분유 및 건조호박 내 Cronobacter의 선택 분리능을 realtime PCR법과 함께 비교하였다. 분유에서의 Cronobacter 검출률은 세 가지 방법에서 유의적인 차이를 나타내지 않았으나(p < 0.05), 건조호박의 경우 R&F배지와 real-time PCR법이 DFI에서보다 유의적으로 높은 검출률을 보였다 (p < 0.05). 배지 간 선택성에 있어서도, R&F 선택배지는 건조호박에서 DFI에 비해 유의적으로 높은 선택성을 나타냈다(p < 0.05). Real-time PCR 및 R&F배지의 사용은 분유뿐만 아니라, 건조 호박 등의 높은 경쟁세균총을 갖는 영유아식의 원료로 사용될 수 있는 식품군에서도 Cronobacter를 효과적으로 검출할 수 있는 방법으로 사료된다.

본 연구는 칼슘과 철 그리고 철과 아연의 상호작용과 신뢰성있는 영양정보를 제공하기 위해 영양강조표시제품중 칼슘, 철, 아연의 함량을 분석하고 표시량과 분석값을 비교하였다. 칼슘, 철, 아연을 강조표시한 제품(시리얼, 과자, 두유, 초콜릿가공품, 기타코코아가공품, 당류가공품, 과줆채음료, 고형차) 총 42건을 수거하였으며 칼슘, 철, 아연은 무기성분의 건식분해법으로 전 처리한 후 Inductively Coupled Plasma Spectrometer (ICP)로 실험하였다. 칼슘이 강조표시된 제품 42건에 대한 표시량 비율은 87~176%이 었으며, 철이 강조표시된 제품 13건에 대한 표시량 비율은 84~167%, 아연이 강조표시된 제품 6건에 대한 표시량비율은 98~275%였다. 모든 분석값이 표시량 대비 80% 이상으로 식품 등의 표시기준을 충족하였다. 칼슘과 철의 상호작용은 한국인의 칼슘 섭취가 1일 권장량의 68.7% 수준으로 부족하므로 칼슘의 과다섭취로 인한 철의 흡수방해는 우려할 만한 상황은 아닌 것으로 보인다. 또한, 분석한 영양강조표시제품의 철과 아연의 함량 비율이 1.53:1이 최대였으므로 철의 과다섭취로 인한 아연의 흡수방해는 우려할 만한 상황은 아니었다. 그러나 업체에서는 칼슘, 철, 아연을 강조한제품을 생산할 시에 영양소의 상호작용을 고려하여 생산을 해야 할 것이고 소비자에게 정확한 영양정보를 제공하고 적정량의 영양섭취를 위해서는 지속적인 모니터링을 통해 식품표시에 대한 주기적인 관리가 필요할 것으로 생각된다.

In this study, two commercial PCR and ELISA test kits were examined for identification of eight animal species (beef, pork, chicken, duck, turkey, goat, lamb, and horse) from raw meat and meat products in Korea. The detection limit in RAW meat ELISA kit® on three types of meat samples blended with beef, pork and chicken, demonstrated that all meat species were differentiable down to 0.2%. RAW meat ELISA kit® on animal species resulted in differentiation rate of 94.5% for beef, 93.3% for pork, 90% for lamb, and 100% for chicken, duck, turkey, goat, and horse. In contrast, Powercheck Animal Species ID PCR kitTM resulted in 100% specificity at 0.05% limit of detection for all meat species. The detection limit of Cooked Meat ELISA kit® on mixed meat samples heat-treated with different temperatures and times, resulted in 0.1% for all heat-treated mixed meat except for chicken at 1.0%. Additionally, ELISA kit on sixty meat products resulted in specificity of 31.8% for ham, 13.6% for sausages, and 12.5% for ground processed products, and relatively low rate for more than 2 types of mixed meats. On the contrary, meat species differentiation using PCR kit showed higher percentage than that using ELISA kit®: 50.0% for ham, 41.7% for sausages, and 28.6% for ground processed meat. Futhermore, PCR kit on 54 dried beef meats detected pork genes in 13 products whereas ELISA kit showed negative results for all products. Hence, the possibility of cross-contamination during manufacturing process was investigated, and it was found that identical tumblers, straining trays, cutters and dryers were used in both beef and pork jerky production line, suggesting the inclusion of pork genes in beef products due to cross-contamination. In this study, PCR and ELISA test kits were found to be excellent methods for meat species differentiation in raw meat and heat-processed mixed meat. However, lower differentiation rate demonstrated in case of meat processed products raised the possibility of inclusion of other species due to cross-contamination during manufacturing process.

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.