FDA releases report on 2006 E. coli outbreak

The possible source of E. coli outbreak in spinach that sickened at least 205 people nationwide and engulfed three lives since August 23, 2006 when the first case was reported, has been traced to spinach from a single California field processed on a single day, according to a joint report released Friday by the Food and Drug Administration (FDA) and California's Department of Health Services (CDHS).

In their joint report, based on an extensive investigation into the causes of an E.coli O157:H7 outbreak last fall that was associated with contaminated Dole brand Baby Spinach, the state and federal investigators said that the spinach was grown on a 50-acre field owned by Paicines Ranch, which breeds Angus cattle and quarter horses, in the San Benito County town of Paicines.

The ranch leases a small amount of cropland to Salinas-based Mission Organics, a spinach grower. 26 samples of cattle feces, wild pig feces, soil and surface water at the ranch matched the genetic strain in bags of spinach that triggered the outbreak.

It was the first time authorities had isolated a bacterial contamination to its potential source using DNA matching, officials said. "The probe was a notable effort by federal, state and local officials," said Robert E. Brackett, Ph.D., director of FDA's Center for Food Safety and Applied Nutrition. "It yielded valuable information we can use to determine how best to reduce the likelihood of similar outbreaks."

California Food Emergency Response Team (CalFERT), a group of experts from FDA's district office in San Francisco and CDHS, conducted the investigation for six months. They were assisted by experts from the Centers for Disease Control and Prevention (CDC) and Animal and Plant Health Inspection Service of the U.S. Department of Agriculture.

The inquiry at first focused on the processing and packaging plant of Natural Selection Foods, LLC in San Juan Bautista, CA, where the contaminated products had been processed. And, then it centralized on the source of the spinach in 13 bags containing E.coli O157:H7 isolates that had been collected nationwide from sick customers. Using the product codes on the bags, and employing DNA fingerprinting on the bacteria from the bags, the investigators were able to match environmental samples of E.coli O157:H7 from one field to the strain that had caused the outbreak.

The long-awaited reports of the joint federal and state investigation point to one California-grown crop and one processing plant, named Natural Selection Foods packaging plant in San Juan Bautista, but the investigators say they still couldn't determine exactly how the spinach became contaminated.

"No obvious sources for introduction of the pathogen were identified at the processing facility. However, a number of conditions were observed that may have provided opportunities for the spread of pathogens, if pathogens arrived on incoming spinach," the report says.

"We'll never be able to make a definitive link, but this shows the inherent risk in the area," said Patti Roberts, a spokeswoman for the health department. "Hopefully that's what good agricultural practices can address to reduce the risk in the future."

In a brief statement on its Web site, the Paicines Ranch, which raises about 2,000 head of grass-fed cattle in the area, said that it leases land to crop growers, and was not under investigation in the outbreak.

Mission Organics head Otto Kramm has told about his plans to build an $80,000 fence on the 450 acres he leases from Paicines Ranch to prevent pigs from going through the area to feed on grapes in neighboring vineyards.