Listeria spp., in churn storage of raw cow’s milk in Tunja - Boyacá

Objective. To determine the relationship between the type of detergent, time use of the churn and the type of water used to wash storage churns and the presence of Listeria spp., in samples collected from storage churns of raw cow's milk, in farms of Tunja-Boyacá-Colombia. Materials and methods. 293 samples were collected by non-probabilistic sampling at convenience, in a period of time of 9 months. Isolation of Listeria spp., was performed by microbiological methods and species identification using biochemical tests. A questionnaire was applied to assess the associated factors (the type of detergent, time use of the churn and the type of water used to wash storage churns). Results. The prevalence of L. monocytogenes was 2.7% (n=8). No statistically significant association was found between the variables related to cleaning of churns and the presence of L. monocytogenes. Conclusions. The existence of L. monocytogenes in raw milk was demonstrated, being the prevalence found lower than those reported in national and international studies. It is evidenced the circulation of species of Listeria in the dairy production chain in Boyacá. On the other hand, it is the first overview of L. monocytogenes and L. ivanovii showing the need for the implementation of control measures in the dairy industry.