Biocontrol of Listeria monocytogenes on fresh-cut produce by treatment with lytic bacteriophages and a bacteriocin
Biocontrol of Listeria monocytogenes on fresh-cut produce by treatment with lytic bacteriophages and a bacteriocin
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DOI：
10.1128/aem.69.8.4519-4526.2003
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发表时间：
2003-08-01
影响因子：
4.4
通讯作者：
Sulakvelidze, A
中科院分区：
文献类型：
--
作者：
Leverentz, B;Conway, WS;Sulakvelidze, A
在过去的10年里，鲜切农产品行业一直是食品零售市场中增长最快的部分，为消费者提供了方便和营养的食品。然而，新鲜切割的水果和蔬菜引起了食品安全问题，因为暴露的组织比完整的农产品更容易被致病菌定植。这是由于切割表面上的营养物质的可用性更高，并且由于处理量的增加，污染的可能性更大。结果表明，施用单核细胞增生李斯特菌在10℃贮藏的鲜切红鲜苹果上存活，且在7天内仅略有增加，而在10℃贮藏的鲜切蜜瓜上显著增加。此外，我们还通过喷雾和移液两种噬菌体施用方法，检测了单核细胞增生乳杆菌对人工污染的鲜切瓜和苹果中单核细胞增生乳杆菌种群的影响。与对照相比，噬菌体混合物使单增乳杆菌的数量减少2.0 ~ 4.6个对数单位。苹果的减少量低于0.4个对数单位。与nisin（一种细菌素）联合使用，与对照相比，噬菌体混合物在蜜瓜片上减少了最多5.7个对数单位，在苹果片上减少了最多2.3个对数单位。与对照相比，单用Nisin可使甜瓜片上的单增乳杆菌数量减少3.2 log单位，苹果片上的单增乳杆菌数量减少2.0 log单位。噬菌体滴度在甜瓜片上稳定，在苹果片上迅速下降。喷雾应用噬菌体和噬菌体加nisin减少细菌数量至少与移液管应用一样多。噬菌体治疗的效果还取决于初始浓度的单核增生乳杆菌。
The fresh-cut produce industry has been the fastest-growing portion of the food retail market during the past 10 years, providing consumers with convenient and nutritious food. However, fresh-cut fruits and vegetables raise food safety concerns, because exposed tissue may be colonized more easily by pathogenic bacteria than intact produce. This is due to the higher availability of nutrients on cut surfaces and the greater potential for contamination because of the increased amount of handling. We found that applied Listeria monocytogenes populations survived and increased only slightly on fresh-cut Red Delicious apples stored at 10degreesC but increased significantly on fresh-cut honeydew melons stored at 10degreesC over 7 days. In addition, we examined the effect of lytic, L. monocytogenes-specific phages via two phage application methods, spraying and pipetting, on L. monocytogenes populations in artificially contaminated fresh-cut melons and apples. The phage mixture reduced L. monocytogenes populations by 2.0 to 4.6 log units over the control on honeydew melons. On apples, the reduction was below 0.4 log units. In combination with nisin (a bacteriocin), the phage mixture reduced L. monocytogenes populations by up to 5.7 log units on honeydew melon slices and by up to 2.3 log units on apple slices compared to the control. Nisin alone reduced L. monocytogenes populations by up to 3.2 log units on honeydew melon slices and by up to 2.0 log units on apple slices compared to the control. The phage titer was stable on melon slices, but declined rapidly on apple slices. The spray application of the phage and phage plus nisin reduced the bacterial numbers at least as much as the pipette application. The effectiveness of the phage treatment also depended on the initial concentration of L. monocytogenes.