Stecchini M L, Aquili V, Sarais I
Dipartimento di Scienze degli Alimenti, Università degli Studi di Udine, Italy.
Int J Food Microbiol. 1995 May;25(3):301-10. doi: 10.1016/0168-1605(94)00093-l.
The behavior of Listeria monocytogenes (Scott A) on fully processed Italian Mozzarella cheese was examined in presence and in absence of bacteriocins produced by Lactococcus lactis ssp. lactis strains (DIP 15 and DIP 16). These strains, isolated from raw milk, produced heat stable bacteriocins that were inactivated by pronase, alpha- chymotrypsin and proteinase K, but not by pepsin, trypsin and catalase. The addition of crude bacteriocins to the growing culture of Listeria monocytogenes resulted in a significant reduction in cell number at 5 degrees C, but not at 30 degrees C. Mozzarella cheese was inoculated with the Listeria culture to obtain an initial level of approximately 30 CFU/cm2 surface of Mozzarella and approximately 10(3) CFU/ml of the surrounding fluid and then packaged in bags containing the heat-treated neutralized-cultures of Lactococcus lactis ssp. lactis in skim milk (in Italy, Mozzarella is sold in small size pieces, individually packaged in bags containing some fluid). Bags were stored at 5 degrees C up to 21 days. The presence of bacteriocins resulted in apparent death of Listeria monocytogenes after 24 h storage. After 7 days of storage, a revival of Listeria monocytogenes was observed, followed by an increase in number. However, for a storage period of 2-3 weeks the number of Listeria monocytogenes remained significantly below the number observed for Mozzarella cheese packaged in absence of the heat-treated cultures of Lactococcus lactis.
研究了单核细胞增生李斯特菌（斯科特A）在有无乳酸乳球菌乳酸亚种（DIP 15和DIP 16）产生的细菌素存在的情况下，在完全加工的意大利马苏里拉奶酪上的行为。这些从生牛奶中分离出的菌株产生了热稳定的细菌素，该细菌素可被链霉蛋白酶、α-胰凝乳蛋白酶和蛋白酶K灭活，但不能被胃蛋白酶、胰蛋白酶和过氧化氢酶灭活。向单核细胞增生李斯特菌的生长培养物中添加粗细菌素，在5℃时细胞数量显著减少，但在30℃时没有减少。用李斯特菌培养物接种马苏里拉奶酪，以使马苏里拉奶酪表面初始水平约为30 CFU/cm²，周围液体约为10³ CFU/ml，然后包装在装有热处理过的乳酸乳球菌乳酸亚种脱脂牛奶中和培养物的袋子中（在意大利，马苏里拉奶酪以小块形式出售，单独包装在装有一些液体的袋子中）。袋子在5℃下储存长达21天。细菌素的存在导致储存24小时后单核细胞增生李斯特菌明显死亡。储存7天后，观察到单核细胞增生李斯特菌复苏，随后数量增加。然而，在2至3周的储存期内，单核细胞增生李斯特菌的数量仍显著低于在没有热处理过的乳酸乳球菌培养物包装的马苏里拉奶酪中观察到的数量。
