College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
Key Laboratory of Environment Correlative Dietology, Huazhong Agricultural University, Wuhan 430070, Hubei, China; College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
Food Res Int. 2018 Sep;111:631-641. doi: 10.1016/j.foodres.2018.05.071. Epub 2018 Jun 1.
Application of bacteriophages to eliminate foodborne pathogens in food matrices is an emerging research field. In this study, a promising phage candidate specific for Salmonella strains was screened and its ability to decrease Salmonella counts in some food, such as milk, sausage, and lettuce, was investigated. A total of 58 Salmonella phages were isolated from a wastewater treatment plant, sewage near a river, farm ditch near a lake, and poultry house. Among them, phages LPST10, LPST18, and LPST23 were highly efficient in infecting Salmonella Typhimurium ATCC 14028. In particular, phage LPST10 could infect all the tested Salmonella Typhimurium and Salmonella Enteritidis strains with high efficiency. Bacterial challenge tests revealed that phage LPST10 and its combination with phages LPST18 and LPST23 could consistently inhibit the growth of multiple strains. Phage LPST10 presented a lysis time of about 50 min with a burst size of 101 PFU/CFU, exhibited two distinct phases in the one-step growth curve, and was stable at a pH range of 3-13 that corresponds to the pH of most of the foods (pH 3.5-7.5) and at temperatures between 30 °C and 60 °C. Transmission electron microscopy demonstrated that phage LPST10 belongs to the Siphoviridae family, with an icosahedral head with a diameter of 83.26 nm and tail length and width of approximately 144.89 nm and 10.9 nm, respectively. A significant decrease in the bacterial counts (0.92-5.12 log CFU/sample) and an increase in phage titers (0-2.96 log PFU/sample) were observed in different food matrices tested. These results demonstrated that phage LPST10 is a promising candidate for controlling Salmonella contamination in foods owing to its safety and effectiveness.
噬菌体在食品基质中消除食源性病原体的应用是一个新兴的研究领域。在本研究中，筛选出了一种针对沙门氏菌的有前途的噬菌体候选物，并研究了其在一些食品（如牛奶、香肠和生菜）中降低沙门氏菌数量的能力。从污水处理厂、河流附近的污水、湖泊附近的农田沟渠和家禽场共分离到 58 株沙门氏菌噬菌体。其中，噬菌体 LPST10、LPST18 和 LPST23 对肠炎沙门氏菌 ATCC 14028 的感染效率很高。特别是，噬菌体 LPST10 可以高效感染所有测试的鼠伤寒沙门氏菌和肠炎沙门氏菌菌株。细菌挑战试验表明，噬菌体 LPST10 及其与噬菌体 LPST18 和 LPST23 的组合可以持续抑制多种菌株的生长。噬菌体 LPST10 的裂解时间约为 50 分钟，爆发量为 101 PFU/CFU，在一步生长曲线中有两个明显的阶段，在 pH 3-13 的范围内稳定，这与大多数食品的 pH（pH 3.5-7.5）和 30-60°C 之间的温度相对应。透射电子显微镜表明，噬菌体 LPST10 属于肌尾噬菌体科，具有一个直径为 83.26nm 的二十面体头部和一个大约 144.89nm 的尾长和 10.9nm 的尾宽。在不同的食品基质中，细菌计数显著减少（0.92-5.12 log CFU/样品），噬菌体滴度增加（0-2.96 log PFU/样品）。这些结果表明，噬菌体 LPST10 是一种很有前途的控制食品中沙门氏菌污染的候选物，因为它的安全性和有效性。
