This year's big foodborne threat is killer tomatoes. Two years ago, spinach up and vanished from grocery store shelves around the country. Michael Pollan will be the first to tell you why: "Eighty percent of America's beef is slaughtered by four companies, 75 percent of the precut salads are processed by two and 30 percent of the milk by just one company." The consolidation of the industrial food supply necessarily means that any pathogen which enters the system will have no trouble finding its way to your dinner plate, heedless of global distances.
Compounding that problem, we have the issue of antibiotics being administered as a preventative measure in livestock and poultry. Animals are routinely fed these medicines as part of their diet, whether they are sick or not. This indiscriminate use has undoubtedly led to a reduced efficacy of antibiotics in humans. Dr. Arjun Srinivasan, a medical epidemiologist with the CDC, notes that we don't know whether overuse of antibiotics in humans is ultimately worse than overuse in animals, but that "there are those who say, if you look at the absolute amount of antibiotics that are used in animals, [it] vastly outweighs the amount that's used in humans. So therefore, that may actually be a larger component" of the problem.