(Feb. 27, 12:30 p.m.) After a yearlong investigation, the California Food Emergency Response Team (CalFERT) has determined lettuce tainted with E. coli served at Taco John’s restaurants in Minnesota and Iowa in late 2006, sickening 80 people, was grown on the Wegis Ranch, Buttonwillow, Calif.

CalFERT, comprised of investigators from the Food and Drug Administration and the California Department of Public Health, investigated growing regions in Kern, Santa Barbara and Santa Maria counties, according to a public health department report released Feb. 15.

Other growers in the investigation, according to the report, included Teixeira Farms Inc., A&A Farms and PacFresh Produce Inc., in Santa Maria, Calif.; Mahoney Bros. Ranch and Byrd Farms, both of Guadalupe, Calif.

The California investigation began Dec. 15, 2006, and almost immediately began to focus specifically on Wegis Ranch because of its proximity to two dairies.

According to the report, irrigation water and dairy effluent conveyance systems, which the central California grower controls, were combined. This raised concern of possible cross-contamination between fields of lettuce and the dairies.

CalFERT determined Wegis Ranch grew iceberg lettuce for the fresh market and tomatoes for processing on its own ground, as well as lettuce and cucumbers for processing on landed owned by the West Star North Dairy that encompassed the suspected contaminated field. Wegis Ranch owned this land until it was sold to two dairies in 2003, but continued to maintain control over the water system.

Prior to the establishment of the dairies, the system was used to route irrigation water from the local water district to the fields.

After the dairies were built, the system became a blend of dairy wastewater (20%) and district water (80%), which was supposed to be used only on fields where feed crops were grown.

Michael Young, co-owner of Wegis Ranch, stated in the report that waste water was never used in the lettuce fields.

But when CalFERT investigators learned of the blending practice, they expanded the environmental investigation and samples collected from the Maya Dairy and the West Star North Dairy matched the E. coli strain they were searching for.

Investigators determined the Wegis Ranch irrigation system was connected to the two dairies through at least two water district pipelines that were not fitted with backflow devices. These devices would have supposedly protected the district water from being contaminated by the manure water.

Of 251 samples taken in the three counties, 32 from the Buttonwillow area proved positive for E. coli O157:H7. All were from the Wegis Ranch and the two dairies. Ten of the samples matched the strain of the Taco John’s outbreak.

Ultimately, the tainted lettuce from Wegis Ranch was processed by Bix Produce, St. Paul, Minn., and distributed through Roma of Minnesota, Rice, Minn., to the Taco John’s restaurants.

On Sept. 24, 2007, five Taco John’s franchisees filed lawsuits against the two companies. The suit did not involve the franchise corporation in Cheyenne, Wyo.

Calls to Wegis Ranch were not returned.