Zajac M, Gladys J, Skarzynska M, Härnulv G, Björck L
Institute of Cattle Breeding and Milk Production, Warsaw University of Agriculture, 05-840 Brwinow, Poland; Alfa-Laval Agri International AB, P.O. Box 39, S-147 00 Tumba, Sweden; and Department of Animal Husbandry, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden.
J Food Prot. 1983 Dec;46(12):1065-1068. doi: 10.4315/0362-028X-46.12.1065.
Preservation of the quality of raw milk by activation of its natural lactoperoxidase (LP) system was studied. The milk was stored at 4, 10 and 17°C for a total period of 104, 72 and 48 h, respectively. At 4°C, the LP system was activated after 48 and 96 h. At the higher storage temperatures, activation was carried out initially and after 24 h and (at 10°C) 48 h of storage. The results show that, at 4°C, the Standard Plate Count in LP-activated milk remained fairly unchanged for at least 104 h, whereas bacterial multiplication in the controls started after 48 h. At 10°C, an activation resulted in a lag-phase of at least 72 h, but at 17°C this was reduced to below 24 h. The observed changes in the counts of coliforms and psychrotrophs followed the same general pattern. These results suggest that activation of the LP system in combination with moderate cooling (e.g., with available well water) could be a useful alternative to extend the keeping quality of raw milk. Overnight storage might then be possible, provided the initial hygienic quality of the milk is good and the milk is promptly taken care of in the morning.
研究了通过激活生乳的天然乳过氧化物酶（LP）系统来保存其质量。牛奶分别在4、10和17°C下储存，总时长分别为104、72和48小时。在4°C时，LP系统在48小时和96小时后被激活。在较高的储存温度下，最初以及储存24小时后（在10°C下为48小时后）进行激活。结果表明，在4°C时，LP激活的牛奶中的标准平板计数至少在104小时内保持相当稳定，而对照组中的细菌繁殖在48小时后开始。在10°C时，激活导致至少72小时的滞后期，但在17°C时，该滞后期缩短至24小时以下。观察到的大肠菌群和嗜冷菌数量的变化遵循相同的总体模式。这些结果表明，激活LP系统并结合适度冷却（例如，使用可用的井水）可能是延长生乳保存质量的一种有用替代方法。如果牛奶的初始卫生质量良好且早上能及时处理，那么隔夜储存可能是可行的。
