Safety and quality assessment of hot-drinks vending machines in Southern Italy

Vending machines (VMs) are common and convenient sources of various food and beverage items. Due to limited available information, concerns have been raised about the hygiene and safety of products dispensed by VMs. This study aims to assess the microbiological contamination of VMs in the Campania region (Italy), by combining microbiological and molecular biology analyses. The results revealed notable microbial contamination in VMs. Total Viable Count exceeded acceptable limits in VMs components, particularly in the inner walls of beverage dispensing nozzles and in the hot-drink product. Coffee and ginseng powders exhibited comparatively lower Total Viable Count values, while chocolate displayed none. Regarding pathogens, Listeria monocytogenes and Salmonella spp. were not detected in any of the samples subjected to analysis. Bacillus cereus (B. cereus) and Staphylococcus aureus (S. aureus) were detected in various VMs components. B. cereus contamination was prevalent, exceeding 80% in some surface swabs (water intake pipe, mixer bowl, and dispensing nozzle), and coincided with a high occurrence in the hot-drink final product. S. aureus was frequently found in milk powder, dispensing nozzles, and cappuccino samples. This research offers valuable insights into VM hygiene and safety, emphasizing the importance of multifaceted approaches to address microbiological contamination and promote public health. Regulatory compliance with cleaning procedures and proactive measures, such as robust self-monitoring plans and adherence to Good Manufacturing Practices, are crucial in mitigating contamination hazards and safeguarding product quality.