When you don’t want to know about food: Raw Milk

November 20th, 2008

Raw milk is what you get straight from the cow. Before they do anything to it and make it for sale to most of us. In most countries raw milk is illegal because it may have harmful microbes we would rather not ingest. So when you get your milk it has already been pasteurized by heating it up to high temperatures in order to kill some of that harmful bacteria.

Raw milk is still available in some parts of the world, as there are those that would argue that raw milk benefits outweigh the risks of the bacteria that can be held within. Some people believe the health benefits resulting from the extra nutrient content of raw milk outweigh the risk of ingesting potentially dangerous microbes, such as Mycobacterium bovis, which can cause tuberculosis, and Salmonella. No thanks.

Now scientists have discovered a new species of bacteria that can grow at low temperatures, spoiling raw milk even when it is refrigerated. Contamination of course can spoil the milk much faster and force you to dump it down your vessel sinks drains, but scientists have discovered more bacteria in raw milk than had previously been studied.

“When we looked at the bacteria living in raw milk, we found that many of them had not been identified before,” said Dr Malka Halpern from the University of Haifa, Israel. “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.”

Raw milk is consumed in rural areas of Europe and is also available in large cities. Distribution of unpasteurised milk is legal in England, Wales and Northern Ireland but illegal in Scotland. There are around 275 establishments in England that are approved by the Food Standards Agency to sell raw milk. However, the green-top bottles must display a warning that indicates the content has not been heat-treated and may contain harmful organisms. Furthermore, farmers are not allowed to sell unpasteurised dairy products if their herd is suspected to be infected with bovine tuberculosis.

“In Israel, dairy companies estimate that cold-tolerant bacteria can cause a 10% loss of milk fats and proteins. When researchers looked at these bacterial communities, they found that 20% of the bacteria isolated were found to be novel species and 5% of these were members of the genus Chryseobacterium,” said Dr Halpern. “Because of their effect on milk quality, it is important that we develop sensitive and efficient tools to monitor the presence of these cold-tolerant bacteria.”

Moral of the story: You might want to stick to pasteurized milk.