Concerns and solutions for raw milk from vending machines

Abstract

The sale of raw milk from vending machines is allowed in several European Countries. Since unpasteurized milk could harbor foodborne pathogens, the boiling treatment is highly recommended before consumption. In this study, the effect of storage temperatures, generally recorded in domestic refrigerators, as well as the effect of domestic boiling and industrial microwaving on the microbiological, and nutritional quality of raw bovine milk from vending machines was evaluated. Results highlighted that some microbial groups increased during the storage at 8°C. Noticeable, Listeria spp., even if initially present in low amounts, reached levels that would be a cause of concerns. Based on these results, the effects of domestic boiling and microwaving on the survival of L. innocua intentionally added was evaluated, as well as the nutritional features of treated milk. Both treatments were able to eliminate L. innocua, but only microwaving preserved the nutritional quality of milk. Practical applications This study presents the application of microwaving as an alternative treatment to enhance the quality of raw bovine milk. Domestic storage conditions (especially refrigeration temperatures and time) produce a strong decay in the microbiological quality of the product and Listeria levels might become a real concern. In addition, boiling treatment, imposed by law prior to milk consumption, produces a further depletion of the nutritional quality, producing a strong decay in thermolabile compounds. A suitable solution for heat treatment of raw milk from vending machines could be represented by microwaving at 780 W for 1.35 min. This datum could serve for setting a specific program in domestic microwave ovens for sanitization of raw milk in home environments.

Low-Fat and High-Quality Fermented Sausages

“…Listeria monocytogenes ( L. monocytogenes ) ATCC 15313 and four strains of Listeria innocua ( L. innocua ), the strain ATCC 33090 and the strains Li03, Li12, Li13, belonging to DIAAA-University of Molise collection [ 46 ], were used as indicator strains.…”

“…Briefly, about 10 g of samples were decimal diluted in a sterile solution of 0.1% peptone water, homogenised in a Stomacher 400 Lab-blender (Seward Medical, London, UK) for 3 min and serially diluted under the same sterile solution. Counts of lactic acid bacteria (LAB), micrococci and staphylococci coagulase- negative cocci (CNC), enterococci, Brochothrix thermosphacta , Listeria spp., total and faecal coliforms, Pseudomonas spp., and Eumycetes were detected after appropriate incubation in proper media and conditions as described in a previous study [ 30 , 46 , 50 , 51 ]. Results were expressed as the mean of measurements reported as Log CFU/g.…”

Growth interferences between bacterial strains from raw cow's milk and their impact on growth of Listeria monocytogenes and Staphylococcus aureus

“…However, there is increasing interest in on‐farm sale of raw milk and pathogens were even detected in pasteurised milk, either due to heat‐resistance or post‐pasteurisation contamination (Mullan 2019; Pannella et al . 2019; Berge and Baars 2020). Listeria monocytogenes and Staphylococcus aureus are the major pathogens associated with consumption of raw milk and raw milk products, and outbreaks occur regularly (Fusco et al .…”