Microbiological evaluation of hot beverages dispensed by vending machines from the Army barracks of Brigata Meccanizzata Aosta located in Messina

The aim of the present study was to evaluate the microbiological quality of hot beverages dispensed by vending machines (VMs). The study was carried out on 203 samples from 15 VMs located in 5 Army barracks in Messina. The samples included: water used for preparation of beverages, swab of water tank, swab of blender machine, chocolate powder, milk powder, cappuccino and chocolate drink (29 samples for each types). All samples were examined for total bacterial count (TBC), coliforms, Escherichia coli, enterococci, Pseudomonas aeruginosa, Staphylococcus aureus, Clostri - dium perfringens, Aeromonas spp., Salmonella spp. and Listeria monocytogenes. For the water samples the colony count (CC) at 22°C and at 37°C was made. The average values of CC at 22°C and at 37°C were of 10.86x10²±8.72x10² CFU/mL and of 21.72x10²±16.44x10² CFU/mL, respectively. P. aeruginosa, coliform bacteria, S. aureus, E. coli and molds were detected from water. The TBC ranged from 176 CFU/g (±275.2) for chocolate powder to 294.8±69.4 CFU/g for milk powder. S. aureus and molds were isolated from milk powder, while coliforms, E. coli and S. aureus were observed in chocolate powder. The average TBC for hot beverages ranged from 34.32x10³±97.77x10³ CFU/mL for cappuccino to 36.59x10³±10.47x104 CFU/mL for chocolate drink. Coliforms, E. coli, enterococci and molds were detected from cappuccino, while enterococci and molds were observed in chocolate drink. The microbiological characteristics of the water and powders, hygiene, and the periodic cleaning of machines, influenced the microbiological quality of the hot beverages dispensed by VMs.