Why Is Milk Pasteurized?
Milk is an excellent medium for microbial growth, and when stored at ambient temperature bacteria and other pathogens soon proliferate. Milk is pasteurized to kill any bacteria, germs in it that might make us sick, and to keep the milk wholesome for many days.
Pasteurization is the reason for milk’s extended shelf life. High-temperature, short-time pasteurized milk typically has a refrigerated shelf life of two to three weeks, whereas ultra-pasteurized milk can last much longer, sometimes two to three months.
In pasteurization, fresh milk is heated to a temperature at which most of the disease forming germs that may be in the milk are killed. The milk is then chilled quickly to preserve its flavor and to keep harmful germs from multiplying again.
The word “pasteurize” comes from the name of Louis Pasteur, the French scientist who discovered how to keep germs from spoiling food. Milk as it comes from the cow is known as “raw” milk.
The US Centers for Disease Control (CDC) says improperly handled raw milk is responsible for nearly three times more hospitalizations than any other food-borne disease outbreak, making it one of the world’s most dangerous food products.
Pasteurization accomplishes two things: Destruction of certain disease-carrying germs and the prevention of souring milk. These results are obtained by keeping the milk at a temperature of 145 degrees to 150 degrees F. for half an hour, at least, and then reducing the temperature to not more than 55 degrees F.