It is commonly know that milk is pasteurized but what does this mean? Pasteurizing is a process that kills any bacteria that may be in the milk to ensure the milk is wholesome. The process was invented by Louis Pasteur, a French scientist. Milk is simply heated in the pasteurizing process, at a certain temperature bacteria cannot survive in milk. There are two different pasteurizing processes. One heats milk to 143 degrees fahrenheit for 30 minutes, the second heats milk to 160 degrees fahrenheit for at least 15 seconds. The first pasteurized milk in America was sold in New York City in 1895. Now all of our store bought milk is pasteurized.