antibiotics in food
Egregious overuse (in beef, poultry, pork) encourages the development of resistant strains of bacteria that then may migrate into the environment at large, including perhaps human bodies. Corporatized agriculture cuts costs and boosts profits by growing the chickens or hogs faster, often in brutal conditions, then somebody else (usually the taxpayers) pays to fight new strains of disease. The biggest pork producer is Smithfield Farms.