This week's episode of John Oliver focused on food safety. One key point: a lot of vegetable farms are collocated with animal factory farms, so runoff from the factory farms that contains fecal bacteria often contaminates the produce – one of the many harms of factory farming. Excerpt below:

John Oliver: One of the biggest vulnerabilities in our current system actually has to do with leafy greens. They are overseen by the FDA and are a major source of food contamination. And one of the key reasons for that is that large industrial farms have become more common with livestock raised extremely close to where crops are being grown, and sometimes even sharing a water source....

Lance Price, Ph.D.: How we raise animals can fuel the growth of these bugs. So if we crowd the animals together, and you have one that's carrying a really bad pathogen like E. coli 157, then they can poop those bacteria out, and then the shit from the cattle washes off into the streams or into ... irrigation canals. And then those can be used to water these plants. You have this distribution system for these pathogens from animals to produce.

Also, both the USDA and the FDA are responsible for food safety for different kinds of food in the US, but the FDA has fewer resources to enforce food safety requirements than the USDA does. The USDA is in charge of many types of meat while the FDA is in charge of everything else, including produce. And the FDA pays more attention to the drugs side of its mandate than the food side. Both of these factors have led to a lot of contamination incidents involving produce.