What did Fleming say about his penicillin?

In 1945 Alexander Fleming, the man who discovered penicillin, warned that overuse of his miracle drug could make bacteria immune to it. He was right — and not just about penicillin: the Centers for Disease Control and Prevention has estimated that antibiotic-resistant bacteria infect more than two million people a year, at least 23, 000 of whom die. A significant part of that overuse, the CDC says, involves feeding the drugs to the animals we eat. Farmers do this not to cure or prevent disease but simply to make livestock grow bigger and faster.
   In 2013 the Food and Drug Administration finally stepped in, asking drug companies to stop selling antibiotics for the purpose of promoting the growth of animals by December 2016. The agency still allows the use of these drugs for "disease prevention" , however — that is, to fight off infections animals have not yet gotten. In principle, it might sound reasonable. In practice, this loophole may be big enough to allow farmers to continue with what they have been doing all along, raising concerns that the FDA’s plan will not amount to much.
   To make things worse, the FDA resisted developing a meaningful plan to evaluate the effect of its action. Instead it intends simply to rely on sales data from drug companies to see whether its (nonbinding) guidelines are actually working. These data are far from ideal for this purpose; even the agency acknowledges that sales are not a reliable way to gauge how antibiotics are really being used.