In Italy, the sale of raw milk from vending machines has been allowed since 2004. Boiling treatment before its use is mandatory for the consumer, because the raw milk could be an important source of foodborne pathogens. This study fits into this context with the aim to evaluate the microbiological quality of 30 raw milk samples periodically collected (March 2013 to July 2013) from 3 vending machines located in Molise, a region of southern Italy. Milk samples were stored for 72 h at 4°C and then subjected to different treat- ments, such as boiling and microwaving, to simulate domestic handling. The results show that all the raw milk samples examined immediately after their collec- tion were affected by high microbial loads, with values very close to or even greater than those acceptable by Italian law. The microbial populations increased during refrigeration, reaching after 72 h values of about 8.0 log cfu/mL for Pseudomonas spp., 6.5 log cfu/mL for yeasts, and up to 4.0 log cfu/mL for Enterobacteria- ceae . Boiling treatment, applied after 72 h to refriger- ated milk samples, caused complete decontamination, but negatively affected the nutritional quality of the milk, as demonstrated by a drastic reduction of whey proteins. The micr owave treatment at 900 W for 75 s produced microbiological decontamination similar to that of boiling, preserving the content in whey proteins of milk. The microbiological characteristics of raw milk observed in this study fully justify the obligation to boil the raw milk from vending machines before consump- tion. However, this study also showed that domestic boiling causes a drastic reduction in the nutritional value of milk. Micr owave treatment could represent a good alternative to boiling, on the condition that the process variables are standardized for safe domestic ap- plication.
|Digital Object Identifier (DOI):||10.3168/jds.2013-7744|
|Codice identificativo Scopus:||2.0-84897231583|
|Appare nelle tipologie:||1.1 Articolo in rivista|