Monitoring the microbial status of raw and pasteurized milk from vending machines in Brandenburg, Germany

In Germany milk vending machines offering raw or pasteurized milk, are an increasingly popular form of milk marketing for direct sellers. The number of milk filling stations in the state of Brandenburg has almost tripled in 2017. Since September 2017, more than 100 raw and pasteurized milk samples from 18 milk filling stations have been examined. Varying microbial counts for total aerobic and psychrotrophic count and Enterobacteriaceae were observed during monitoring, indicating a wide quality spectrum of milk from vending machines. Approximately one third of all samples exceeded at least one microbial reference value. In order to assess health risks under the assumption of direct consumption, the raw milk samples were additionally tested for typical food-pathogens. Pathogens were detected by PCR in about 29 % of these samples. The dominant microorganism flora was identified by MALDI-TOF mass spectrometry from the total bacterial count and discussed with the respective operational process conditions of production as well as cleaning and disinfection. The resulting multi-stage controls showed above all hygienic weak points for the participating farms, e. g. in the milking area, by a probable interruption of the cold chain and especially in the implementation of established cleaning and disinfection procedures of the milk pipes/storage tanks and milk dispensers. Based on these results, operation-based corrective measures were proposed to optimize the organizational and hygienic working methods and processes.