Washington, D.C. ? In an effort to prevent more illnesses from bacteria-tainted produce, the U.S. Food and Drug Administration on Monday announced voluntary guidelines for processors of prepackaged fruits and vegetables, the fastest-growing sector of the produce industry.

The list of steps to minimize the spread of bacteria includes recommendations for multiple washings of the produce, cold storage, regular water testing and monitoring of employees for signs of infectious disease. Many processing and packaging companies already follow the federal guidelines, which were first proposed a year ago.

The national guidelines will apply to bagged spinach, shredded lettuce, salad mixes, baby carrots, cut melons, broccoli florets and other fresh-cut produce.

But critics in Congress and at consumer groups say voluntary is not enough when numerous lethal outbreaks of food-borne illnesses already have been traced back to produce.

Rep. Rosa L. DeLauro, D-Conn., who co-chairs the Congressional Food Safety Caucus, said the FDA was missing its chance to take action when the public wants protection and the food industry wants help restoring its image. The new FDA document “does nothing and merely tells growers what they already know,” said DeLauro, who chairs the House Appropriations Agriculture Subcommittee.