Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk
Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk
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DOI：
10.3168/jds.s0022-0302(00)74873-9
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发表时间：
2000-02-01
影响因子：
3.5
通讯作者：
Boor, KJ
中科院分区：
文献类型：
--
作者：
Ma, Y;Ryan, C;Boor, KJ
在乳房内感染无乳链球菌之前四次和之后四次从八头荷斯坦奶牛身上收集牛奶。感染后牛奶的体细胞计数 (SCC)（849,000 个细胞/ml）明显高于感染前牛奶（45,000 个细胞/ml）。高SCC原料奶比低SCC原料奶具有更多的脂肪分解和蛋白水解作用。将感染前和感染后的巴氏灭菌、均质、2% 脂牛奶储存在 5°C 下，并在加工后 1、7、14 和 21 天时分析脂肪分解、蛋白水解、微生物质量和感官属性。在冷藏过程中，高 SCC 牛奶中游离脂肪酸增加（即脂解）和酪蛋白水解的平均速率分别比低 SCC 牛奶快三倍和两倍。一般来说，高 SCC 牛奶和低 SCC 牛奶的标准平板计数、大肠菌群计数和耐冷细菌计数仍然较低（
Milk was collected from eight Holstein cows four times before and four times after intramammary infection with Streptococcus agalactiae. Postinfection milk had significantly higher somatic cell count (SCC) (849,000 cells/ml) than preinfection milk (45,000 cells/ mi). High SCC raw milk had more lipolysis and proteolysis than low SCC raw milk. Pasteurized, homogenized, 2% fat milks from pre- and postinfection periods were stored at 5 degrees C and analyzed for lipolysis, proteolysis, microbial quality, and sensory attributes at 1, 7, 14, and 21 d post processing. During refrigerated storage, the average rates of free fatty acid increase (i.e., lipolysis) and casein hydrolysis in high SCC milk were, respectively, three and two times faster than those in low SCC milk. In general, standard plate counts, coliform counts, and psychrotrophic bacterial counts of both the high and low SCC milks remained low (