Elizabeth Armstrong did not give the Food and Drug Administration much thought until her children became ill from eating contaminated bagged spinach.

Her two-year-old daughter, Ashley, one of more than 200 people affected by the outbreak of E. coli 0157:H7 in spinach last year, is still dealing with the effects of kidney failure. Today she is off dialysis and home from the hospital. But she is on daily medication and will eventually need a kidney transplant, said her mother, who lives with her family in a suburb of Indianapolis.

The incident galvanized Ms. Armstrong, turning her into something of a food-safety activist. Testifying before Congress in April, she said that the Food and Drug Administration, the agency responsible for regulating much of the food we eat, including spinach, needed to be reformed.

The agency has known about contamination issues with fresh produce for 10 years, she said in a telephone interview. "They have sent threatening letters to growers and packagers, but they never stepped in and told them they need to change their operations," she continued.

"You live in the United States of America and this isn't supposed to happen. There is an assumption that everything is going to be O.K., that someone must have checked this out, but it is not the case."

Ms. Armstrong is one of many people demanding an overhaul of the agency. The cause gained momentum in the past year as at least three people died and more than a thousand were sickened by contaminated tomatoes, lettuce, peanut butter and spinach. But the recent contamination of pet food, which has killed many animals, seems to have been the last straw.

Leaders in the food industry and three former secretaries of the Department of Health and Human Services have joined longtime critics to form the Coalition for a Stronger F.D.A., which seeks agency reform, in part by giving it more money and regulatory authority. A few small changes were made in an amendment attached to the F.D.A. reauthorization bill that passed in the Senate last week.

Dr. Andrew C. von Eschenbach, the agency's commissioner for the last 18 months, is well aware of the criticism. He said much more is expected of the agency than in the past. "I think as people have greater expectations we need to have commensurate increases in resources," he said. And, he added, "we need to continue to expand our regulatory authority."

Dr. von Eschenbach believes the agency can achieve its goals through voluntary guidelines. But the fresh-cut produce industry, hit hard by outbreaks in recent years, has been virtually begging for stronger intervention.

Tom Stenzel, president and chief executive of the United Fresh Produce Association, said the industry's problems "can't be solved without strong mandatory federal regulations."

But after seven years of discussions about food safety advice on the farm, the agency has issued only voluntary guidelines; not even hand-washing is mandatory. After the E. coli outbreaks last year, sales of bagged spinach dropped 60 percent in October. Today sales are still down 20 percent.

For at least six years polls have shown public concern about the agency. One, conducted in September by Opinion Research Corporation for the Coalition for a Stronger F.D.A., found that only 30 percent of the 1,000 randomly selected participants had a great deal of confidence that the agency could ensure the safety of their food.

In testimony before Congress this month, Dr. David A. Kessler, a former agency commissioner, offered a bleak view of the current situation. "Our food safety system is broken," he said.

This year the nonpartisan Government Accountability Office, the investigative arm of Congress, added the country's food safety system to its list of "high risk" operations. The fact that 12 different agencies have some responsibility for food safety does not help, said a G.A.O. report, which recommended that all food safety matters be regulated by one agency.