초고압 처리한 생굴의 저장 중 미생물수 및 품질 변화

Abstract

Raw oysters were treated at 10℃ and 22℃/350 MPa/15 min, and microbial counts and quality were measured during storage of 14 days at 10℃. Total viable cell count (TVCC) in untreated oyster increased greatly during storage from starting inoculum of 1.6×10<SUP>2</SUP> CFU/mL, and reached to 5.6×10<SUP>4</SUP> CFU/mL after 4 days of storage. TVCC of the pressure-treated was about 10<SUP>1</SUP> CFU/mL right after high hydrostatic pressure treatment and increased slowly during storage, and about 10<SUP>3</SUP> CFU/mL even after 7 days of storage. Lactic acid bacteria count (LABC) in the untreated was increased greatly during storage from starting inoculum of 3.3×10<SUP>3</SUP> CFU/mL at 3 days of storage, and 7.2×10<SUP>4</SUP> CFU/mL after 4 days of storage. LABC in the pressure-treated was detected only after 5 days of storage, and about 10<SUP>2</SUP> CFU/mL after 8 days of storage. The pH of the untreated was 6.19 and decreased gradually during storage, and 5.83 after 4 days of storage. The pH of the pressure-treated showed little change during storage, and 6.07, 6.03 and 5.82 after storage of 4, 8 and 14 days, respectively. Volatile basic nitrogen (VBN) in the untreated was 16.8 mg%, and maintained almost constant until 1 day of storage, and then increased suddenly, and 30.1 mg% after 4 days of storage. VBN of the pressure-treated stayed unchanged during storage, and about 20 and 23 mg% even after 4 and 8 days of storage, respectively. Hunter L<SUP>*</SUP>, a<SUP>*</SUP> and b<SUP>*</SUP> values were increased until 2 days of storage and then showed no change during storage. Demerit score was the lowest in the thawed raw oyster, and then in the increasing order of the pressure-treated(4 day and 8 day storage) and the untreated (4 day storage).