FDA inspectors, for example, visited the ConAgra plant on Feb. 14, a day after the Centers for Disease Control and Prevention told the agency it suspected the company's peanut butter was the source of the outbreak.

For one member of Congress, that's not good enough.

"We are reacting to crises rather than preventing or minimizing them," said Rep. Rosa DeLauro, D-Conn., chairwoman of the House subcommittee that oversees the FDA and its budget. DeLauro said she worried food inspections were becoming a "stepchild" of the regulatory agency.

Von Eschenbach said the agency's food safety system can be reactive but is aggressive nonetheless.

"What you saw with the spinach and certainly what you saw with the peanut butter, is when we see those signals we're going to act to protect the public health," von Eschenbach said.

In the meantime, the House Committee on Energy and Commerce is investigating the adequacy of the FDA's efforts to protect the nation's food supply, Rep. Bart Stupak, D-Mich., said.

A recent Government Accountability Office report noted that most of the $1.7 billion the federal government allocates to food safety goes to the Agriculture Department, which is responsible for regulating about 20 percent of the food supply. The FDA, responsible for most of the other 80 percent, gets about 24 percent of the total.

When the FDA finds violations with a food product, it asks companies to voluntarily fix any problems. The agency also can request a company to recall a product or it can ask that a product be seized by law enforcement.

The Agriculture Department said this month it also would switch to a "risk-based" inspection plan for plants that process poultry, pork and beef. Plants that make products with a high risk for contamination, like hamburger, and that have had past violations would face greater scrutiny. Others than make less risky products, like cooked, canned ham, and have clean records would be inspected less.