International Center for Food Industry Excellence, Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas 79409-2141, USA.
J Food Prot. 2009 Nov;72(11):2278-83. doi: 10.4315/0362-028x-72.11.2278.
Lactic acid bacteria (LAB) can decrease numbers of Escherichia coli O157:H7 and Salmonella in ground beef during storage. Two dose-titration studies were conducted in ground beef to determine dose levels of LAB needed to inhibit the pathogens. A second study evaluated whether LAB masked changes typically associated with the spoilage of ground beef displayed under refrigerated (0 degrees C) or abusive (10 degrees C) temperatures packaged in both traditional overwrap (TOP) and modified atmosphere packaging (MAP; 80% O(2)-20% CO(2)). Microbial analyses were conducted to determine spoilage endpoints and pathogen reduction. In the dose-titration study, Salmonella was reduced by 3 log cycles at all doses (10(6), 10(7), and 10(8) LAB per g) after 3 days of storage and was eliminated after 5 days of storage. E. coli O157:H7 was reduced by 2 log cycles at all dosages after 3 days of storage and by 3 log cycles after 5 days of storage. In the spoilage studies, as expected, total aerobic plate counts and LAB populations in LAB-inoculated samples were higher than the controls initially, but the counts were similar near the end of the study. While total spoilage bacteria generally increased over time, very few differences existed between treatments stored at 0 degrees C and 10 degrees C in coliforms, Brochothrix thermosphacta, yeasts and molds, and Pseudomonas spp. counts for both the TOP and MAP samples. We conclude that LAB could potentially be added to ground beef in TOP and MAP as a processing intervention for E. coli O157:H7 and Salmonella without masking microbial spoilage characteristics.
乳酸菌（LAB）可以减少牛肉中大肠杆菌 O157:H7 和沙门氏菌的数量。在牛肉中进行了两项剂量滴定研究，以确定抑制病原体所需的 LAB 剂量水平。第二项研究评估了 LAB 是否掩盖了冷藏（0°C）或恶劣（10°C）温度下包装的传统包装（TOP）和改良气氛包装（MAP；80%O2-20%CO2）下显示的碎牛肉变质的典型变化。进行微生物分析以确定变质终点和病原体减少。在剂量滴定研究中，在 3 天的储存期后，所有剂量（10（6），10（7）和 10（8）LAB/g）的沙门氏菌减少了 3 个对数循环，并且在 5 天后储存期后被消除。在 3 天的储存期后，所有剂量的大肠杆菌 O157:H7 减少了 2 个对数循环，在 5 天的储存期后减少了 3 个对数循环。在变质研究中，正如预期的那样，接种了 LAB 的样品中的总需氧平板计数和 LAB 种群最初高于对照，但在研究结束时计数相似。虽然总腐败细菌随着时间的推移而普遍增加，但在 0°C 和 10°C 下储存的处理之间，在大肠菌群、热纤维菌、酵母和霉菌以及假单胞菌计数方面，TOP 和 MAP 样品之间几乎没有差异。我们得出结论，LAB 可以作为一种加工干预措施，添加到 TOP 和 MAP 中的碎牛肉中，以减少大肠杆菌 O157:H7 和沙门氏菌，而不会掩盖微生物变质特征。
