The following information was taken (but not quoted) from the book, Mental Floss Presents: Condensed Knowledge. I highly recommend it as a source of general scientific knowledge. It also covers a large number of other fields.
The pasteurization process was developed (appropriately enough) by Louis Pasteur (1822-1895) in the 1860s. The proper heat treatment of certain foods—such as milk, eggs and cider—can neutralize germs without altering the taste of these foods. This discovery was a huge breakthrough on the part of Pasteur. It is only fitting that this process was named after him. Thanks to him, fresh milk is now readily availabe on a wide scale basis.
Pasteur was also the one who demonstrated that spontaneous generation does not occur. Up until that point, people believed that living beings appeared like magic—frogs in wet mud, maggots in meat,and so forth. By demonstrating that maggots do not spontaneously appear out of decaying meat, Pasteur introduced a quantum leap in preventing communicable diseases.