Use this fact to answer the question: Louis Pasteur invented pasteurization

Milk sold in supermarkets is pasteurized because

Choose your answer from:
(1). all raw milk is safe;
(2). to keep bacteria from getting into the milk after the customer buys it;
(3). the factory farmed cows produce a lot of pus in their milk;
(4). that makes it taste better;

The answer is:
(2).