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New Study Reveals Bacteria in Unprocessed Milk

written by: Nicky LaMarco•edited by: Niki Fears•updated: 11/29/2008

Drinking milk has long been considered an important part of good health. Milk is a wonderful source of calcium which can prevent bone loss later in life. However, recent research has discovered new reasons why drinking unprocessed or “raw" milk can be a very dangerous thing to do.

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    Bacteria in Milk

    Milk has always been swarming with bacteria. From the cow’s body to the milking equipment, there are plenty of opportunities for nasty bacteria to get into the milk and to get into anyone drinking that milk. Food scientists once believed that by immediately refrigerating the milk the growth of the bacteria could be stopped. Today, these scientists know that cold-tolerant bacteria do exist. In fact, they grow and spread quickly in the refrigerated environment and can even cause milk to spoil. Three such organisms have been discovered thus far in samples of raw milk: C. oranimense, C. haifense, and C. bovis. Researchers are uncertain about the effects these bacteria may have on the milk or even on how they survive the cold environment but more research will be done to find the necessary answers.

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    Debate over Raw Milk

    The discovery of the cold-tolerant bacteria in raw milk has caused a resurgence in the debate over the benefits and risks of consuming milk in this way. Some argue that pasteurization destroys many of the important nutrients found in raw milk. However, the dangers of consuming unprocessed milk have long been known. In fact, French physician Louis Pasteur created the pasteurization process to ensure that milk was safe to drink. By heating the milk, the bacteria can be killed off thanks to his process.

    Some of the bacteria found in raw milk can be pretty nasty. Mycobacterium bovis is one example. This bacterium can cause tuberculosis. Drinking unprocessed milk can also expose you to some types of salmonella and a wide range of other scary microbes. For this reason, the selling of raw milk has been made in illegal in many countries. Even when it can be sold legally, that part of the dairy industry is heavily regulated and the containers must be specially marked.

    Of course, pasteurization does have some drawbacks. Some of the bacteria are not killed at these temperature levels. Others release enzymes when heated, and these enzymes can damage the flavor of milk and cheeses.

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    Continuing Steps

    Ensuring the safety of the West’s milk supply is important. Even those who favor raw milk recommend taking actions to keep it save, such as preventing milk from herds possibly affected by bovine tuberculosis to be sold unpasteurized.

    Of course, safety isn’t the only concern. Both heat-tolerant and these newly identified cold-tolerant bacteria can have a negative impact on the taste and quality of the milk. As researchers continue deciphering their mysteries, these issues will slowly become a concern of the past.