28 Nov : Here’s an advice for milk lovers — just don’t drink it raw as scientists have discovered new species of bacteria that can grow at low temperatures, spoiling raw milk even when it is refrigerated.
Dr Malka Halpern, who the research team at University of Haifa in Israel said: "When we looked at bacteria living in raw milk, we found that many of them had not been identified before.
"We have now identified and described one of these bacteria, Chryseobacterium oranimense, which can grow at cold temperatures and secretes enzymes that have the potential to spoil milk.
"In fact, we found that 20 per cent of the bacteria isolated were found to be novel species and five per cent of these were members of the genus Chryseobacterium."
According to the scientists, the discovery is vital in determining the risks of drinking unpasteurised milk."Milk can be contaminated with many different bacteria from the teat of the cow, the udder, milking equipment and the milking environment.
"Milk is refrigerated after collection to limit the growth of microbes. During refrigeration, cold-tolerant, or psychrotolerant, bacteria that can grow at 7C dominate the milk flora and play a leading role in milk spoilage.
"Although we have not yet determined the impact on milk quality of C. oranimense and two other novel species (C. haifense and C. bovis) that were also identified from raw milk samples, the discovery will contribute to our understanding the physiology of these organisms and of complex environmental processes in which they are involved," Dr Halpern said.
The findings are published in the ‘International Journal of Systematic and Evolutionary Microbiology’.