One-third of samples of milk and dairy products analysed in various restaurants in Europe are contaminated, says a new study.

Researchers from the University Of Valencia (UV) advised against keeping milk in jugs and suggest that these foodstuffs need to be better handled. The team detected unsuitable practices, such as reheating milk over and over again, even in a microwave, and then pouring it back into the thermos, which increases the risk of microbial contamination. The study shows that there is a greater contamination risk from milk kept in jugs.

"Out of all the dairy products we analysed, 35 percent of the samples exceeded the maximum contamination levels established by EU law for enterobacteriaceae, and 31 percent exceeded the limits set for mesophilic aerobic micro-organisms. The latter grow at an optimum temperature of between 30 and 45 degrees Celsius," said Isabel Sospedra, UV researcher in preventive medicine and public health and a study co-author, according to SINC.

Two percent of the samples of hot milk (kept in jugs or stainless steel thermos flasks) also tested positive for the bacteria E. coli. The scientists examined 265 batches of milk and ready to use milk derivatives in a range of bars and restaurants in Valencia, and checked whether their microbial quality fell into line with European Union (EU) regulations. The results show that one-third of the samples had some kind of micro-organism contamination and were not fit for human consumption. "Luckily none of the batches we analysed tested positive for Staphylococcus aureus, Listeria monocytogenes or Salmonella spp., which are pathogenic micro-organisms that cause both food poisoning and toxoinfections," the study authors say.