Investigators are still unsure how cooked rotisserie chicken sold at a Costco store in South San Francisco was contaminated with a strain of salmonella involved in a national outbreak linked to Foster Farms brand poultry.
At least one person was sickened by one of the chain's roasted chickens, prompting Costco to order a recall over the weekend of nearly 40,000 pounds of rotisserie chicken products sold between Sept. 11 and Sept. 23 from the store at 1600 El Camino Real.
The U.S. Department of Agriculture and Foster Farms have assured consumers that poultry contaminated with salmonella is safe to eat so long as its cooked to a minimum of 165 degrees Fahrenheit.
Costco rotisserie chicken is cooked to at least 180 degrees Fahrenheit, said Craig Wilson, Costco's vice president for food safety.
"It was well-cooked," Wilson said Monday. How someone got sick is "part of the mystery."
He added: "It may have been a very, very uncommon cross-contamination issue. We're still researching."
In total, Costco recalled 8,730 Kirkland Signature Foster Farms rotisserie chickens and 313 units of Kirkland Farm rotisserie chicken soup, rotisserie chicken leg quarters and rotisserie chicken salad.
Wilson said the company contacted 7,807 customers who had bought one or more of the recalled products. So far, no one else has reportedly fallen ill, he said.