건조식품의 상대습도 및 온도별 저장조건에 따른 미생물학적 안전성 평가 = Microbial Levels of Dried Foods Stored at Various Relative Humidity and Temperature Conditions

다국어 초록 (Multilingual Abstract)

The purpose of this study was to evaluate microbial levels of dried anchovy, shrimp, aster scaber, and shiitake stored at different temperatures (25 and 35℃) and relative humidity levels (RH 50, 70, and 90%) for 15 days. Samples were analyzed for total aerobic plate counts (APCs), coliforms, Escherichia coli, yeasts & molds (MY), and water activity (aw). Initial water activities of dried foods (aster scaber, shiitake, anchovy, and shrimp) were 0.66, 0.43, 0.55, and 0.62, respectively. Water activities of dried foods at relative humidity levels (50, 70, and 90%) were 0.49∼0.59, 0.65∼0.78, and 0.83∼0.96 during 15 days storage respectively. At 90% RH which was a good environment for bacteria, yeasts, and molds to live, it was presumed that microorganism increased in number. The initial APC levels were 6.1 log CFU/g for aster scaber, 2.7 log CFU/g for shiitake, 3.6 log CFU/g for anchovy, and 3.4 log CFU/g for shrimp. The initial populations of MY were 1.2 log CFU/g for aster scaber, 2.2 log CFU/g for shiitake, and 1.3 log CFU/g for anchovy, respectively. In dried shrimp, no MY were found. The initial coliforms and E. coli were below detection limit (<1.0 log CFU/g) in all samples. No significant changes were shown in samples during 15 days storage at 25, 35℃, and RH 50%. At 25 and 35℃ storage temperature, and 70% RH environment, there were slight changes. The populations of microorganisms increased continuously in all samples after 3 days of storage at 25, 35℃ and RH 90% conditions. Under 35℃ and RH 90% environment after 3 days, the populations of APC have increased to 7.3, 7.9, 8.8, and 6.7 log CFU/g for aster scaber, shiitake, anchovy, and shrimp, respectively. The MY levels have increased to 7.8, 7.3, 5.8, and 7.3 log CFU/g for aster scaber, shiitake, anchovy and shrimp, respectively, after 15 days at 35℃, RH 90%. All samples had no significant effect on coliforms and E. coli population at all storage environment.
Results showed at high temperature and relative humidity had on great effect on the growth of microorganism in dried food. Expiration date of dried foods should be controlled to secure safety. Therefore, dried aster scaber and shiitake, which should be after opening the package consumption in 5 days at 25℃ and 90% RH and in 3 days at 35℃ and 90% RH. Dried anchovy and shrimp, which necessary be consumption in 3 days at 25℃ and 90% RH and in 1 day at 35℃ and 90%. These results suggest that precautions should be taken to keep the appropriate conditions, especially in temperature and humidity, for storage and distribution of dried food.

목차 (Table of Contents)

• 목차 ⅰ
• List of Tables ⅲ
• List of Figures ⅳ
• Ⅰ. 서 론 1
• Ⅱ. 연구배경 4
• 1. 외식업소의 식중독 발생 현황 4
• 2. 식재료의 안전성 평가 6
• 3. 건조식품의 안전성 9
• 1) 건조식품의 기준·규격 9
• 2) 건조식품의 안전성 평가 11
• Ⅲ. 실험 내용 및 방법 13
• 1. 저장 환경 설정 13
• 2. 시료 준비 및 보관 13
• 3. 시료의 채취 15
• 4. 수분활성도 측정 15
• 5. 미생물 분석 15
• 1) Aerobic plate counts 16
• 2) Coliforms 과 E. coli 16
• 3) Yeast 와 mold 16
• 6. 통계 분석 16
• Ⅳ. 결과 및 고찰 18
• 1. 수분활성도 18
• 2. 미생물 분석 21
• 1) 건 취나물 21
• 2) 건 표고버섯 27
• 3) 건 멸치 33
• 4) 건 새우 40
• Ⅴ. 요약 및 결론 47
• 참고문헌 51
• Abstract 67