Robert Brackett, director of the Food and Drug Administration's Center for Food Safety and Applied Sciences, said Tuesday it "is increasingly likely they will never zero in on the source."

    Brackett's comments came after agency inspectors pored over water quality reports, worker hygiene tests and other food safety measures in an effort to discover how the bacteria made it into spinach grown and bagged in California. The bacteria caused one death and sickened more than 100 people across the country.

    At least two lawsuits over youngsters who fell ill have already been filed, in New York and Utah.

    FDA investigators visited fields and factories in the Salinas Valley that have been linked to the two companies that recalled spinach products ¡ª Natural Selection Foods and River Ranch Fresh Foods.

    "They will look for any obvious or even suspected places where this organism could gain access to the produce," said Brackett.

    Farmers in the self-proclaimed "Salad Bowl to the World" started plowing their spinach crops under and laying off workers as government inspectors examined fields and packing houses Tuesday for the source of the deadly E. coli outbreak.

    The teams also inspected other locations, looking for evidence of contaminated runoff; checking for animal droppings in the fields; examining sanitary conditions inside the plants where produce is processed; and taking samples from produce itself. E. coli is commonly spread by human or animal feces.

    "At least two lawsuits over youngsters who fell ill have already been filed, in New York and Utah.

    "If it stays focused on the spinach, it's still bad," said Jim Bogart, president of the Grower-Shipper Association of Central California. "Worse-case scenario, where consumers don't get the message this doesn't mean all vegetables are tainted, it would be devastating."

    The current E. coli outbreak is at least the eighth food-poisoning episode traced to the Salinas Valley since 1995. Local growers were already working with the Food and Drug Administration to improve produce-handling procedures before the multistate outbreak occurred, said Bogart.

    "What we would like them to do is take ownership of the problem. The fact that this keeps coming up suggests that whatever has been done is not good enough."

    Spinach was a 325 million U.S. dollar industry in the U.S. in 2005, and California produced 74 percent of the nation's fresh crop and 67 percent of the spinach that gets frozen or canned. The Salinas Valley accounts for roughly three-quarters of the state's share. Enditem

    (Agencies)