Right...because before the state department came along companies had no interest in feeding their patrons safe food... People are incredibly unscientific when attributing success to governmental regulatory bodies.
Obviously restaurants had an interest in food safety. You're being a little silly with your sarcasm. The question is whether food was as safe as we (citizens) wanted, and whether food safety would improve with government regulation. I suspect the answers were "No" and "Yes", respectively.
Take recent issues at Chipotle for example. Without government intervention, they easily might decide that it's cheaper to pay marketers and public relations experts than to improve the safety of their supply chain and service.