MODESTO — According to an update from the Centers for Disease Control and Prevention, the salmonella outbreak traced to Foster Farms chicken has grown to a total of 430 people sickened.
Since the CDC's last update on Dec. 19, 14 more people have been reported ill: 11 cases in California and one each in Arizona, Idaho and Virginia. Overall, since the first report of the outbreak in October, 74% of the cases have been in California.
There have been no deaths reported from the outbreak, but of the 359 people on whom the CDC had information, 38% reported they had been hospitalized. The CDC's update Thursday also said 13% of the ill developed blood infections and that "typically, approximately 5% of persons ill with salmonella infections develop blood infections."
"The number of reported infections from the outbreak strains of Salmonella Heidelberg has returned to baseline levels, indicating that this particular outbreak appears to be over," the update states.
"However, activities related to this investigation are ongoing. Illnesses that occurred after Dec. 15 might not be reported yet due to the time it takes between when a person becomes ill and when the illness is reported. This takes an average of two to four weeks."
A CDC representative on Friday called the "return to baseline" good news for Foster Farms and said it indicates the company has taken effective measures to bring the salmonella outbreak under control.
In explaining the salmonella outbreak investigation, Ian Williams, chief of the CDC's Outbreak Response and Prevention Branch, said, "We work backward from the genetic fingerprint of the organism that made them sick, which in this case was Salmonella Heidelberg."
Through interviews with those sickened, investigators determined the source was Foster Farms chicken.
There are at least a couple of ways people continue to become ill, Williams said. They may have frozen chicken that they've since thawed and prepared, but not cooked sufficiently to destroy the salmonella. Or they may have purchased chicken anytime since the outbreak, incorrectly believing that any contaminated chicken long since was gone from stores.
Salmonella occurs naturally in chicken, and "chicken can be contaminated no matter what," Williams said. "Always treat it like it is," being careful to cook it thoroughly and, to avoid cross-contamination, washing countertops, knives, cutting boards and utensils that come in contact with the raw chicken.
The U.S. Department of Agriculture's Food Safety and Inspection Service never recalled any Foster Farms chicken because it was not able to link the illnesses to a specific product or production period.
Foster Farms also did not recall any chicken, but a Costco store in South San Francisco voluntarily recalled in October its rotisserie chicken and some other products that originated with Foster Farms.
Mexico also blocked imports of Foster Farms chicken from the three processing facilities — one in Livingston and two in Fresno — linked to the outbreak.
After the outbreak, Foster Farms announced it was improving sanitation and taking other measures that far exceed industry standards. The new measures include more intensive sanitizing of work surfaces and equipment and vaccination against this type of salmonella for the hens and roosters that produce the chickens raised for meat.
On Jan. 8, the Food Safety and Inspection Service ordered production suspended at the Livingston processing plant because of a cockroach infestation.
After the three-day federal shutdown, the company reopened the plant last Saturday, but then voluntarily closed it again Sunday. Foster Farms said the second closure was needed to make sure prevention measures were adequate.
No consumer products are affected, the company said.
As of early Friday afternoon, the plant remained closed, and a public relations spokeswoman representing Foster Farms had no word on when it would reopen.