First, the food supply of the United States is changing dramatically, The conditions under which food animals are raised have changed greatly. Food processing technologies are constantly evolving. The centralization of the food industry means that a single contaminated product may appear in many different foods and many different forms, and infect a considerable number of people before it is identified. Finally, new and emerging foodborne pathogens have been identified, which can cause diseases unrecognized 50 years ago. These include bacteria, parasites, and viruses, along with toxic causes of foodborne illnesses.
Constant vigilance is necessary to identify new problems requiring new solutions as they emerge.
However, despite these new risks, the food supply of the United States is probably safer now than ever.