Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Mississippi State, Mississippi 39762, USA.
Foodborne Pathog Dis. 2010 Apr;7(4):427-34. doi: 10.1089/fpd.2009.0432.
Bacteriophage Listex P100 (phage P100) was approved by the U.S. Food and Drug Administration and U.S. Department of Agriculture's Food Safety and Inspection Service for Listeria monocytogenes control on both raw and ready-to-eat food products. In this article, we present the proof of concept on the influence of phage dose, phage contact time, and storage temperature on the listericidal activity of phage P100 in reducing the L. monocytogenes loads on the surface of fresh channel catfish fillet. The fresh catfish fillet samples were surface inoculated with approximately 4.3 log(10) colony forming units (CFU)/g of a two serotype mix (1/2a and 4b) of L. monocytogenes cells and then surface treated with phage P100. L. monocytogenes reduction was influenced by phage contact time and phage dose regardless of higher or lower temperature regimes tested on catfish fillet. The reduction in L. monocytogenes loads (p < 0.05) with the phage P100 dose of 2 x 10(7) plaque forming units (PFU)/g (7.3 log(10) PFU/g) was 1.4-2.0 log(10) CFU/g at 4 degrees C, 1.7-2.1 log(10) CFU/g at 10 degrees C, and 1.6-2.3 log(10) CFU/g at room temperature (22 degrees C) on raw catfish fillet. The phage contact time of 30 min was adequate to yield greater than 1 log(10) CFU/g reduction in L. monocytogenes, whereas 15 min contact time with phage yielded less than 1 log(10) CFU/g reduction in L. monocytogenes loads on catfish fillet. Phage P100 titer was stable on catfish fillet samples, and overall reductions in L. monocytogenes counts were still maintained over a 10-day shelf life at 4 degrees C or 10 degrees C by phage P100 treatment. These findings illustrate the effectiveness of an alternative generally recognized as safe antimicrobial such as bacteriophage Listex P100 in quantitatively reducing L. monocytogenes from fresh catfish fillet surfaces.
噬菌体现已被美国食品和药物管理局以及美国农业部食品安全检验局批准，可用于控制生的和即食的食品中单核细胞增生李斯特菌。在本文中，我们介绍了噬菌体现列 P100 剂量、接触时间和储存温度对其在减少鲜鲶鱼片表面单核细胞增生李斯特菌负荷方面的杀菌活性的影响的概念验证。新鲜的鲶鱼片样本用大约 4.3 log(10) 个菌落形成单位（CFU）/g 的两种血清型混合（1/2a 和 4b）的单核细胞增生李斯特菌细胞进行表面接种，然后用噬菌体现列 P100 进行表面处理。无论在鲶鱼片上测试的温度较高还是较低，噬菌体现列 P100 的接触时间和剂量都影响单核细胞增生李斯特菌的减少。噬菌体现列 P100 剂量为 2 x 10(7) 噬菌斑形成单位（PFU）/g（7.3 log(10) PFU/g）时，在 4°C 下单核细胞增生李斯特菌负荷减少 1.4-2.0 log(10) CFU/g，在 10°C 下减少 1.7-2.1 log(10) CFU/g，在室温（22°C）下减少 1.6-2.3 log(10) CFU/g。噬菌体现列 P100 的接触时间 30 分钟足以使单核细胞增生李斯特菌减少大于 1 log(10) CFU/g，而接触 15 分钟的噬菌体现列 P100 使单核细胞增生李斯特菌减少小于 1 log(10) CFU/g。噬菌体现列 P100 在鲶鱼片样本上的效价稳定，在 4°C 或 10°C 下的 10 天货架期内，噬菌体现列 P100 的处理仍能保持单核细胞增生李斯特菌数量的总体减少。这些发现说明了替代物（如噬菌体现列 P100）的有效性，这些替代物通常被认为是安全的抗菌剂，可以定量减少鲜鲶鱼片表面的单核细胞增生李斯特菌。
