NewYork-Presbyterian. The University Hospital of Columbia and Cornell.

-- Health officials scoured Salina Valley spinach fields earlier this week in search of the source of a massive outbreak of E. coli contamination.

The Sacramento Bee reported that 75 percent of those sickened by tainted spinach were women, including one who died from kidney failure. Twenty victims have hemolytic uremic syndrome, a condition that can lead to kidney failure.

US health officials on Monday expanded their warning to consumers not to eat any fresh spinach at all, as a massive recall by two California produce companies continued.

Numerous Brands Tainted

River Ranch Fresh Foods recalled its brands of mixed salads containing spinach Sunday, after US Food and Drug Administration (FDA) inspectors found that the company had bought spinach from Natural Selection Foods, the focal point of the investigation.

According to the San Jose Mercury News, the recall now involves 37 brands of bagged salad with spinach - 34 from Natural Selection in San Juan Batista and three from River Ranch, which operates in Salinas and El Centro, Calif. Seventy-five percent of the nation's spinach supply comes from the Salinas Valley, a crop estimated to be worth $200 million.

According to the FDA,  Natural Selection Foods supplies its spinach to the following brands that package it:

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

Recurring Problem

The AP reported that nearly a year ago, the FDA  had told California farmers to improve produce safety in a pointed warning letter. This is the 20th food-poisoning episode since 1995 that has been linked to spinach or lettuce, according to the wire service.

The FDA says the first cases of infection apparently surfaced on Aug. 23, and the most recent cases were reported Sept. 17th. But it was not until last Wednesday that the agency was able to identify bagged spinach as the possible cause.

On Tuesday, Sept.19, the Centers for Disease Control and Prevention (CDC) reported a total of 131 reported cases from 21 states. Half of those affected required hospitalization, according to the CDC.

CDC Prepared to Help

Officials at the  CDC meanwhile, have started an emergency operations center in Atlanta to assist state health agencies with testing for the specific strain identified (E. coli 0157:H7).

On Saturday, the government had identified Natural Selection Foods as the focal point of the outbreak. The company began recalling all of its prepackaged spinach and its salad mix products that contain spinach in all brands packed with "Best If Used By" dates of Aug. 17, 2006, through Oct. 1, 2006.

The FDA on Monday also dismissed a claim by Natural Selection Foods that its organic spinach products had been cleared of suspicion, according to the Associated Press. The company, one of the largest in the business, produces both organic and conventionally grown spinach in separate areas at its plant.

"The FDA  has not cleared any products from the list and continues to recommend consumers avoid eating fresh spinach products," spokeswoman Susan Bro says.

Consumers should throw away any fresh packaged spinach they may have bought in the past few weeks and not buy more until the warning is lifted, the agency says. It also says that washing the spinach will not help because the bacteria is too tightly attached.

Always consult your physician for more information.