The U.S. Department of Agriculture's "risk-based" inspection plan immediately drew fire from consumer groups that doubted the agency's ability to determine risk, and from meatpackers complaining that they were blindsided by the plan.

Although the Food Safety and Inspection Service will focus more on plants judged to have a higher risk of contamination, daily inspection will continue at all processing plants, said Richard Raymond, Agriculture under secretary for food safety.

"This new process will take what I think is a very safe food supply and make it safer," Raymond said. If the system works well in the initial plants, its use will expand slowly to other plants.

Consumer groups say the USDA does not have good enough data to know which plants need attention.

Meatpackers say the USDA did not give them details of an untested plan until the last minute.

The USDA says plants will be selected for more attention depending on the type and volume of what they produce -- ground beef is a higher-risk product than smoked ham, for instance -- and their track record in operating safely and preventing contamination.