WWW- Federal health officials last night linked a deadly E. coli outbreak in bagged spinach products to a California farm company that sells organic produce in 74 percent of the country’s grocery stores.

Natural Selection Foods, widely known for its Earthbound Farm brand, yesterday recalled all its fresh spinach products, along with packaged salads. Natural Selection Foods recalled all packages of its fresh spinach and any salad with spinach in a blend because they are possibly contaminated with E. coli. The affected packages have “Best if Used by Dates” of Aug. 17 through Oct. 1. Consumers with questions can contact the company at 800-690-3200.

The recalled brands: Bellissima, Cheney Brothers, Coastline, Compliments, Cross Valley, D’Arrigo Brothers, Dole,Earthbound Farm, Emeril, Fresh Point, Green Harvest, Jansal Valley, Mann, Mills Family Farm, Natural Selection Foods, Nature’s Basket, O Organic, Premium Fresh, President’s Choice, Pride of San Juan, Pro-Mark, Rave Spinach, Ready Pac, River Ranch, Riverside Farms, Snoboy, Superior, Sysco, Tanimura & Antle, The Farmer’s Market, Trader Joe’s

The company also sells products under the Trader Joe’s and Dole brands, among dozens of others.

Many of the people who have become ill reported eating Natural Selection products, but the Food and Drug Administration has not yet found the bacterium in the company’s products. The outbreak has sickened nearly 100 people in 20 states, including one potential case in Virginia.

FDA officials warned consumers not to eat packaged spinach, and last night it extended the warning to packaged salad products that contain spinach, as well as spinach at restaurant salad bars. The strain of Escherichia coli that is making people sick is particularly virulent. The bacteria can cause severe vomiting and diarrhea, and some people can develop kidney failure.

The warnings came on a day when grocery stores and restaurant chains scrambled to pull bagged spinach off their shelves and menus. Wal-Mart Stores Inc. removed its bagged spinach from stores around the country. So did Giant Food, Food Lion and Safeway. Cosi, a popular lunch chain, took baby spinach out of its hand-tossed salad. The Ruby Tuesday restaurant chain decided last night to remove all spinach from its salad bars and entree salads.

At Whole Foods Market, which cleared its stock Thursday after initial FDA warnings, signs were posted explaining to customers why bagged spinach was not on shelves.

“We pulled all our spinach in the store, not only the bagged stuff but any of the fresh stuff and any products that had fresh spinach in them,” said Sarah Kenney, director of marketing for the company’s mid-Atlantic region. The stores communicated with each other via e-mail. “We get questions like: ‘What about the spinach in this dip?’ The response is: ‘Just pull it.’ ”

Spinach is a nearly $300 million-a-year industry and has been growing with the popularity of packaged salads. While sales of canned spinach have fallen 14 percent, to $34 million, from 2002 to 2005, sales of packaged spinach have risen. Sales rose nearly 36 percent from 2002 to 2005, to $158 million, according to AC Nielsen.

“I love spinach,” said Ophelia Miranda, a District resident, who couldn’t find it yesterday at a Whole Foods Market. “I’ll stay away from it for a while.”

Health officials made the link to Natural Selection Foods by interviewing patients, asking them what they had eaten in the week before they became ill, and then looking in the answers for a common thread. Once spinach was implicated, epidemiologists queried the people about where they shopped and what brands they had bought. That led to the California company.

A spokeswoman for Earthbound Farm released a statement saying the company was assisting federal health authorities in their investigation, including providing full access to its facilities and offering products for testing.

“We will do whatever is necessary to help protect the health and safety of the public,” the statement said.

David Acheson, an FDA food safety official, emphasized last night that no E. coli bacteria has been isolated from any of Natural Selection’s products and that recalls could extend beyond Natural Selection Foods. Samples of spinach that several patients still had in their refrigerators are being shipped to FDA labs for testing. Food safety experts have been recently tracking an increase in the number of food-borne illnesses in fresh produce. Outbreaks in produce have been more frequent than beef and poultry in recent years, according to federal health statistics analyzed by the Center for Science in the Public Interest. From 1998 to 2004, there were 492 outbreaks of food-borne illnesses attributed to produce, including 86 in 2004. In the same period there were 324 outbreaks traced to beef, 402 to poultry and 626 to seafood.

Caroline Smith DeWaal, food safety director for the Center for Science in the Public Interest, said it was not clear what caused the increase in produce problems. “What is clear is that the numbers show they are not going down,” she said.

James Gorny, senior vice president for food safety and technology at the United Fresh Produce Association, attributed the increase to several factors, including increased consumption of produce, better detection methods and advances in epidemiology. He said the public is also more aware of problems that could arise from tainted produce.

“We never thought to look at fruits and vegetables before, and now we are,” he said.

Gorny said the industry has improved its communication with regulatory agencies and recently issued guidelines for handling melons, tomatoes, lettuce and leafy greens.

“These documents don’t just sit on a table,” he said. “We really try to get them out to industry.”

Tom Stenzel, president and chief executive of the United Fresh Produce Association, said it is working closely with the FDA to determine the source of the current outbreak. “We’ve got to make sure consumers retain their confidence in the safety of these products,” he said yesterday during a news conference at the National Press Club in Washington.

The outbreak prompted questions about how packaged spinach is produced. Gorny said it is sent to a processing facility after harvesting, where it is cooled and triple-washed in chlorinated water, “probably a more vigorous wash cycle than you can ever do in your home.” The spinach is then dried, packaged and refrigerated before being shipped to distributors.

Raw, bulk spinach is harvested and packaged but not washed before it is sent to distributors, Gorny said. Stenzel cautioned that produce tainted with E. coli cannot be decontaminated simply by washing. “You can certainly reduce risk by washing the product, but you cannot eliminate the risk,” he said.

The only way to eliminate the risk is to cook the product to at least 160 degrees, but health officials advised against that, saying preparing contaminated food could spread the bacteria.