Tests find outbreak strain at Wright County Egg farms, in feed

Aug 26, 2010 (CIDRAP News) – Federal officials today announced that samples from two chicken farms, chicken feed, and feed components at Wright County Egg, one of the two Iowa companies implicated in a nationwide Salmonella outbreak, match the outbreak strain found in sick patients.

At a media briefing today Sherri McGarry, emergency coordinator for the Food and Drug Administration's (FDA's) Center for Food Safety and Applied Nutrition, said the feed sample that tested positive for the Salmonella Enteritidis (SE) outbreak strain also contained a bone meal component that tested positive for the contaminant. The feed was produced at a mill on a Wright County Egg farm and provided to the company's pullets and those of Hillandale Farms, the other company linked to the outbreak and egg recall.

She said the first positive tests suggest that the farms are the likely source of the outbreak, and though the feed appears to be a source, it may not be the only source of SE. McGarry said about 600 samples have been collected so far from about 24 different sources, such as manure, feed, and environmental surfaces. The first set of positive tests show that the DNA fingerprint on pulse-field gel electrophoresis testing matches the outbreak strain.

Investigators haven't linked the contaminated feed to any other farms besides the two at the center of the nationwide egg recall, she said, and are continuing their investigation of the feed and how it became contaminated.

Dr Jeff Farrar, associate commissioner of food protection in the FDA's Office of Foods, said, "We don't know how, when, or where the feed may have become contaminated. It raises additional questions at this point." He said FDA investigators are working hard to finalize the 483 report describing their findings, which he said might be posted on the FDA's Web site within the next few days.

Dr Dan McChesney, director of surveillance and compliance in the FDA's Center for Veterinary Medicine, told reporters that poultry feed production typically includes a heat treatment to kill pathogens and that investigators are probably looking into possible recontamination after that processing step.

The other positive samples were taken from manure and surface areas at two of the farms, federal officials said.

Christopher Braden, MD, acting director of the US Centers for Disease Control and Prevention's (CDC's) division of foodborne, waterborne, and environmental diseases at the National Center for Emerging and Zoonotic Infectious Diseases, told reporters that from May 1 through Aug 25 the CDC has received reports of 2,403 SE illnesses during a time when it would expect to receive about 933 background cases. The increased number of SE reports means that 217 more cases may be linked to the outbreak, up from 1,953 and a background number of 700 cases reported on Aug 23.

He said the CDC hasn't received any more reports of new illnesses clusters beyond the 26 it already knows about, but he said the agency expects to receive more illness reports, given normal delays between when a patient gets sick and his or her illness is confirmed and reported to state and federal officials.

Fortunately, no clusters have been reported in nursing homes, Braden said, noting older people are especially vulnerable to SE infections and that that past SE outbreaks have involved the facilities.

Farrar said federal officials are working as fast as they can to ensure that eggs from two companies are recalled and removed from store shelves, though there is always room for improvement. He said the proposed Food Safety Modernization legislation, currently stalled in the Senate, could have sped the process by improving the traceability system, access to company records, and the government's recall authority.

He said the FDA is still working to identify all eggs that may be contaminated and determine the scope of the recalls. He said he wouldn't be surprised to see more secondary egg recalls linked to distributors who received eggs from the two companies.

Yesterday Trafficanda Egg Ranch, based in Van Nuys, Calif., recalled certain Julian dates of shell eggs that it received from Wright County Egg. The eggs were distributed in grocery stores and foodservice companies in California. The recall applies to egg packaged in 12-egg cartons, 20-egg overwraps, and 5-dozen overwraps and produced from May 16 through Aug 17.

In other developments, Rep Bart Stupak (D-Mich.) has sent a letter to federal food safety officials asking if consumers will be notified when eggs from the two companies that are being pasteurized and sold as liquid eggs and other food components will be included in other food products.

Dr Joshua Sharfstein, MD, principal deputy commissioner at the FDA, said the agency is still assessing Stupak's letter and will reply. The pasteurization process is known to kill Salmonella, but Stupak says consumers should be informed when recalled eggs that go through the process are included in other food products.

A committee that Stupak co-chairs, the US House Committee on Energy and Commerce, has sent letters to Wright County Egg and Hillandale Farms requesting information from the companies, including when they first notified federal officials about the contamination.

See also:

Aug 26 CDC Salmonella outbreak update

Aug 25 Trafficanda egg recall notice

Gift Opportunity

Ebola and Emerging Infectious Disease Fund

Your support is critical to ensure CIDRAP's capacity to respond. Your gift in any amount is deeply appreciated.

Newsletter Sign-up

Get news & practices.

Sign up now»

OUR UNDERWRITERS

Unrestricted financial support provided by

Bentson Foundation 3M United Health Foundation Gilead Become an underwriter»