Raw milk-associated foodborne infections: a scoring system for the risk-based categorisation of raw dairy farms

A pilot study was implemented in the Veneto Region of Italy, aimed at classifying dairy farms which produce milk to be commercialised unpasteurised on the basis of their risk of faecal contamination of milk, which is directly correlated to the probability of a foodborne pathogen, if present in the herd and eliminated through faecal excretion, to contaminate the raw product. Factors considered to be relevant in the definition of the risk of pathogens potentially present in animal faeces to be transmitted to milk, were hierarchically structured, weighted through the application of experts elicitation methods (Analytic Hierarchy Process, Delphi) and used to categorise farms through the application of a herd questionnaire. The probability of faecal contamination of milk, and thus the risk of pathogens transfer appears to be modulated more by farm management than by the structure of the farm or the health status of the herd. Such a method, combined with the microbiological evaluation of the prevalence of faecal excretion of such pathogens, can be used to implement a risk-based surveillance programme and to apply targeted control measures.