Knappstein Karin, Aust Vanessa, Kunz Hans-Jürgen, Kaske Martin
Department of Safety and Quality of Milk and Fish Products, Max Rubner-Institute, Kiel, Germany.
Berl Munch Tierarztl Wochenschr. 2013 Jan-Feb;126(1-2):32-6.
Two commercially available pasteurizers for on farm pasteurization of milk intended for feeding calves were tested for their efficiency to inactivate mastitis pathogens. Raw bulk tank milk of the experimental farm Schaedtbek of the Max Rubner-Institute was artificially contaminated with twelve different strains of mastitis pathogens (intended level 7-8 log10 colony forming units [cfu]/ml). The average contamination level was 7.6 log10 cfu/ml in trials with pasteurizer 1 (P1) and 7.3 log10 cfu/ml in trials with pasteurizer 2 (P2), with lowest counts for yeasts (5.1 log10 cfu/ml for P1 and P2). Average reduction rates of > 5.8 log10 cfu/ml for P1 (72 degrees C, 12 s) and > 6.2 log10 cfu/ml for P2 (64 degrees C, 35 min) revealed an appropriate efficiency of both pasteurizers for practical purposes. Pathogens surviving pasteurization (enterococci in trials with both pasteurizers and of Staphylococcus aureus and Escherichia coli with P1) demonstrate the limits of pasteurization as a function of raw milk quality and emphasize the necessity for appropriate handling of pasteurized milk to prevent excessive multiplication of microbial pathogens.
对两种市售的用于农场巴氏杀菌供犊牛饮用牛奶的巴氏杀菌器进行了测试，以评估其灭活乳腺炎病原体的效率。马克斯·鲁布纳研究所实验农场沙德贝克的散装生牛奶被人工接种了12种不同的乳腺炎病原体菌株（目标水平为7 - 8 log10菌落形成单位[cfu]/ml）。在使用巴氏杀菌器1（P1）的试验中，平均污染水平为7.6 log10 cfu/ml，在使用巴氏杀菌器2（P2）的试验中为7.3 log10 cfu/ml，酵母的数量最低（P1和P2均为5.1 log10 cfu/ml）。P1（72摄氏度，12秒）的平均减少率> 5.8 log10 cfu/ml，P2（64摄氏度，35分钟）的平均减少率> 6.2 log10 cfu/ml，表明两种巴氏杀菌器在实际应用中都具有适当的效率。巴氏杀菌后仍存活的病原体（两种巴氏杀菌器试验中的肠球菌以及P1试验中的金黄色葡萄球菌和大肠杆菌）表明了巴氏杀菌作为生牛奶质量函数的局限性，并强调了对巴氏杀菌牛奶进行适当处理以防止微生物病原体过度繁殖的必要性。
