Half a billion eggs suspected of carrying salmonella have been recalled in what’s become the largest egg recall in U.S. history. And many people are wondering: How did this happen? Is it the fault of the factory farming industry? Or the government? And what can be done to prevent widespread food contamination from happening in the future?

William Neuman has been covering the egg recall for The New York Times. He says this isn't simply a case of corporate farms run amok. Factors he says we should consider:

• The FDA took decades to nail down regulations for salmonella in eggs.
• Their regulations do not include immunization of hens - a measure which has almost entirely eliminated salmonella in eggs in the U.K.
• Even eggs from small, local farms can be contaminated with salmonella, particularly on the outside. All foods come with risks.