Feeding practices associated with the presence of Listeria monocytogenes: a case-control study in New York state dairies.

摘要

We carried out a case-control study to investigate the association of several feeding and silage management practices to the presence of Listeria monocytogenes in milk filters in 404 dairy farms in New York, USA. A total of 94 herds, 47 cases and 47controls were selected from dairy farms enrolled in the Quality Milk Promotion Services (QMPS). Cases were defined as dairy farms in which L. monocytogenes was confirmed in milk filters. Control herds were selected randomly from farms that tested negative for the pathogen. A questionnaire was used to collect data on putative factors in feeding and silage management. The practices were grouped into 2 major categories, general farm feeding practices and silage-related factors, and the significance of association was evaluated using logistic regression analysis. Five factors from the general feeding category were found significant. Component-fed herds, feeding of leftover feed to cows, plastic-type feed bunk, and lower frequency of feed bunk cleaning were positively associated with an increased likelihood of L. monocytogenes, while feeding of dry commercial grains was associated with reduced likelihood. From the silage-related factor category, the response 'never' to the question about observing spoilage in silage on the farms was positively associated with increased presence of L. monocytogenes.