When Pasteurization was first invented many people could and would become ill to certain products due to tainting with certain bacteria and fungi. Additionally these various bacteria would cause the taste of these products to sour.
Originally Pasteur would come up with the method of heating up a certain food or substance, to kill these pathogens, when working to improve the longevity and taste of Wine. His method however is now used around the world for use in purifying Milk and Dairy, Wine, fruit juices, etc... and reducing the risk of food poisoning, while also improving the economics of these products.
They took samples from both the moon, and the earth and compared them to see the similarities and differences