Villani F, Pepe O, Mauriello G, Moschetti G, Sannino L, Coppola S
Istituto di Microbiologia Agraria e Stazione di Microbiologia, Università di Napoli Federico II, Portici, Italy.
Lett Appl Microbiol. 1996 May;22(5):357-60. doi: 10.1111/j.1472-765x.1996.tb01178.x.
The behaviour of a four-strains mixture of Listeria monocytogenes (strains Scott A, V7, OH and Cal) during the traditional manufacture of water-buffalo Mozzarella cheese was investigated at two levels of inoculation: ca 10(5) and 10(3) cfu ml-1 of vat milk. No significant change in Listeria counts was observed during the curd ripening (4.0-4.5 h), at the end of which the pH ranged between 4.83 and 4.91. A decrease of about 2 log was observed after stretching of the curd in hot water (95 degrees C), followed by complete elimination of Listeria after 48 and 24 h of storage of the final cheese in the conditioning liquid (skim water resulting from the stretching, pH ca 4.0) with initial high and low contamination of the cheese milk respectively. Results also indicated that a 1.7 log reduction of L. monocytogenes could be achieved during the preparation of the natural whey culture utilized as starter in cheesemaking.
研究了在两种接种水平下（每毫升大罐牛奶中约含10⁵和10³ cfu），单核细胞增生李斯特菌四菌株混合物（斯科特A、V7、OH和卡尔菌株）在传统水牛奶马苏里拉奶酪制作过程中的行为。在凝乳成熟阶段（4.0 - 4.5小时），未观察到李斯特菌数量的显著变化，此时pH值在4.83至4.91之间。在95摄氏度的热水中拉伸凝乳后，观察到数量下降了约2个对数，随后，在最终奶酪分别以初始高污染和低污染的奶酪乳保存在调理液（拉伸产生的脱脂水，pH约为4.0）中48小时和24小时后，李斯特菌被完全消除。结果还表明，在制备用作奶酪制作发酵剂的天然乳清培养物的过程中，单核细胞增生李斯特菌数量可减少1.7个对数。
