# Assessment of the Microbiological Quality of Raw Milk Sold Through Vending Machines at the Farm Level in Switzerland

## TL;DR

This study assesses the safety of raw milk sold via vending machines in Switzerland and finds potential risks from harmful bacteria.

## Contribution

The study provides new data on the prevalence of foodborne pathogens in raw milk from vending machines in Switzerland.

## Key findings

- Shiga toxin-producing E. coli was found in 3.2% of raw milk samples.
- Yersinia enterocolitica was detected in nearly 30% of samples, indicating hygiene issues.
- MRSA and ESBL-producing bacteria were each found in 0.8% of samples.

## Abstract

The sale of raw milk via vending machines represents a well-established distribution model in many European countries, including Switzerland. As part of this study, data on the microbiological quality of raw milk sold via vending machines in Switzerland were collected. A total of 124 raw milk samples from 124 raw milk vending machines across Switzerland were analysed. In addition to standard hygiene parameters (TVC and E. coli), the scope of the investigation particularly included foodborne pathogens as well as methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. Isolates were further characterised by whole-genome sequencing. Shiga toxin-producing Escherichia coli (STEC) were detected in 3.2%, Staphylococcus aureus was detected in 12.1%, Listeria monocytogenes was detected in 2.4%, Campylobacter spp. were detected in 1.6%, Yersinia enterocolitica was detected in 29.8%, and Salmonella spp. were detected in 0% of the samples. MRSA and ESBL-producing Enterobacterales were each detected in 0.8% of samples. The results highlight the potential risk of foodborne infections associated with the consumption of untreated raw milk, as well as hygiene deficiencies linked to several raw milk vending machines. Based on the generated data, the importance of the requested heat treatment of raw milk in Switzerland is clearly underscored. Furthermore, more precise and binding guidelines for self-monitoring and the management of raw milk vending machines appear necessary.