The United States Food and Drug Administration (F.D.A.) has expanded its search for the source of the deadly E.Coli bacterium that has already killed one woman and sickened more than 100 people.  The outbreak has been linked to bagged spinach but authorities are now warning consumers to avoid all fresh spinach for the time being.

Grocers across the country have been busy pulling bagged spinach from their shelves, but the warning has been expanded to include all fresh spinach, including those mixed in tossed salads.

The F.D.A. says at least 55 people have been hospitalized after eating the tainted greens, 16 of them diagnosed with hemolytic uremia, a type of kidney failure.

Bevan Baker

Hardest hit was the state of Wisconsin where the first cases were reported. Wisconsin Health Commissioner Bevan Baker said, "The key thing to note here is that this could be the tip of the iceberg because we know of 20 confirmed cases. We know individuals have sought medical advice, others who may have been exposed may not have sought medical advice and may not have the severity of illness.  The elderly and the very young are those we are concerned about."

For reasons authorities say are still not clear, 74 percent of the victims have been women.  Among the first was 27-year-old Gwyn Wellborn who got sick after eating spinach salad and spent 13 days in the hospital.

Gwyn Wellborn

"I had food poisoning before,” Gwyn said, “but this was kind of severe so I knew this was something a little different."

E. Coli is a naturally occurring bacterium found in humans and animals.  Doctors say the symptoms are similar to food poisoning and can include severe abdominal pain and diarrhea.  Past outbreaks have been blamed on undercooked meat, but Robert Brackett, the director of the F.D.A.'s Center for Food Safety says irrigation water contaminated by cattle feces may be the likely cause.

Dr. Robert Brackett

"If we could, we'd like to find the brands that might be involved.  We'd like to find the actual lot numbers or lot codes or bag codes so that we could limit the damage to the industry as much as possible,” said Dr. Brackett.

California farms sell about $115 million worth of spinach every year.  Nearly three quarters of it is grown in Monterey County, where farmers were getting ready to harvest. 

Bob Perkins

The County Farm Bureau's Bob Perkins says the E.Coli scare could not have come at a worse time.  "Growers and packers are frustrated right now because nobody wants this sort of problem.  We want to find it, we want to fix it."

Agricultural experts say it is not clear what long-term impact the outbreak could have on consumer buying patterns.  The California Department of Agriculture says Americans buy about $250 million worth of fresh spinach from supermarkets every year.