우리나라 유산양 알코올 양성유의 특징에 관한 연구 (Characteristics of dairy goat milk positive reaction of the alcohol precipitation test in Korea)

서지정보

· 발행기관 : 한국동물위생학회
· 수록지 정보 : 한국동물위생학회지 / 36권 / 4호 / 255 ~ 261페이지
· 저자명 : 김혜라, 정지영, 조인영, 유도현, 신성식, 손창호, 오기석, 허태영, 정영훈, 최창용, 서국현

초록

The objective of the present study was to determine the minimum alcohol(ethanol) concentration that gives rise to the coagulation of goat milk for the alcohol precipitation test, and to evaluate the physical parameters of goat milk which include alcohol and heat stability. A total of 1,295 udder-half milk sam-ples from 648 lactating dairy goats were collected from seven farms in Jeonnam province, Republic of Korea, to determine the alcohol and heat stability. The majority (99.6%) of the samples were coagulated when 70% ethanol was added to the milk, while only 11.0% of the samples were precipitated by the addition of an equal volume of 45% ethanol. With the concentration of 65%, 60%, 55% and 50% aque-ous ethanol, 99.2%, 96.8%, 81.0% and 52.8% of the milk samples were coagulated, respectively. Of 1,295 dairy goat milk samples tested for heat stability, 127 (9.8%) were coagulated by boiling. Among the 143 alcohol test-positive udder-half milk samples, 52 (4.0%) were unstable by heat test, while 1,032 (79.7%) of the 1,152 alcohol test-negative milk samples were stable by heat test. According to the re-sults of boiling test, sensitivity and specificity of 45% alcohol precipitation test were 0.3023 (95% CI: 0.2346∼0.3772) and 0.9190 (95% CI: 0.9017∼0.9344), respectively. The contents of protein and the specific gravity were higher in the milk samples of 45% alcohol test-positive than in those of 45% alco-hol test-negative. However, lower levels of lactose and milk urea nitrogen were observed in the milk samples of 45% alcohol test-positive compared to the alcohol test-negative milk samples. The lowest pH values (6.73±0.20) were shown in the 45% alcohol test-negative and heat-unstable milk samples, while the lowest values of somatic cell counts and bacterial counts were shown in the 45% alcohol test-negative and heat-stable milk samples. Results of this study suggest that the alcohol precipitation for dairy goat milk may have to be tested with ethanol concentration less than 45% for the determi-nation of freshness and heat-stability.

영어초록

The objective of the present study was to determine the minimum alcohol(ethanol) concentration that gives rise to the coagulation of goat milk for the alcohol precipitation test, and to evaluate the physical parameters of goat milk which include alcohol and heat stability. A total of 1,295 udder-half milk sam-ples from 648 lactating dairy goats were collected from seven farms in Jeonnam province, Republic of Korea, to determine the alcohol and heat stability. The majority (99.6%) of the samples were coagulated when 70% ethanol was added to the milk, while only 11.0% of the samples were precipitated by the addition of an equal volume of 45% ethanol. With the concentration of 65%, 60%, 55% and 50% aque-ous ethanol, 99.2%, 96.8%, 81.0% and 52.8% of the milk samples were coagulated, respectively. Of 1,295 dairy goat milk samples tested for heat stability, 127 (9.8%) were coagulated by boiling. Among the 143 alcohol test-positive udder-half milk samples, 52 (4.0%) were unstable by heat test, while 1,032 (79.7%) of the 1,152 alcohol test-negative milk samples were stable by heat test. According to the re-sults of boiling test, sensitivity and specificity of 45% alcohol precipitation test were 0.3023 (95% CI: 0.2346∼0.3772) and 0.9190 (95% CI: 0.9017∼0.9344), respectively. The contents of protein and the specific gravity were higher in the milk samples of 45% alcohol test-positive than in those of 45% alco-hol test-negative. However, lower levels of lactose and milk urea nitrogen were observed in the milk samples of 45% alcohol test-positive compared to the alcohol test-negative milk samples. The lowest pH values (6.73±0.20) were shown in the 45% alcohol test-negative and heat-unstable milk samples, while the lowest values of somatic cell counts and bacterial counts were shown in the 45% alcohol test-negative and heat-stable milk samples. Results of this study suggest that the alcohol precipitation for dairy goat milk may have to be tested with ethanol concentration less than 45% for the determi-nation of freshness and heat-stability.

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