By Lyndsey Layton
Thursday, August 26, 2010; 7:02 PM
Laboratory tests have confirmed that two Iowa egg companies are contaminated with the same strain of salmonella blamed for a national outbreak of illness, which continues to claim victims and has sickened at least 1,500 people, federal officials said Thursday.
The confirmation backs up suspicions by the Food and Drug Administration that tainted eggs from the two Iowa producers have caused the biggest case of Salmonella enteritidis disease that federal officials have seen since they began tracking the illness in the 1970s.
The FDA, which has sent 20 investigators to the two farms - Wright County Egg and Hillandale Farms - said Thursday that it had detected the particular strain of salmonella in two barns at Wright County Egg and in feed that the company made and gave to its own chickens. The agency also found that strain in feed that Wright supplied to Hillandale.
"These are the very first results that we're beginning to get in, and there are many other results in the queue that may give us clues as to the the extent of contamination," said Jeff Farrar, associate commissioner for food protection at the FDA. He said that the agency had taken 600 samples at the farms for laboratory analysis and that additional results were expected.
Officials from Wright County Egg said in a statement that the presence of salmonella on the property did not necessarily mean that the eggs were infected. But the company also pledged to work with the FDA.
It was unclear how the feed or the barns became contaminated with bacteria.
Animal feed is generally heated to kill microbes, so it is possible that the feed became contaminated after it arrived at Wright County Egg, said Josh Sharfstein, deputy commissioner at the FDA.
"The feed facility is at the same location of all these problems," Sharfstein said, referring to Wright County Egg, which operates a feed mill as well as hen-laying facilities and egg-processing plants. "So there are multiple ways it may have become contaminated."
Under federal law, feed that is contaminated with Salmonella enteritidis is considered adulterated, and it is illegal to give it to livestock, Sharfstein said.
Under pressure from the FDA, Wright County Egg and Hillandale recalled about 500 million eggs in the past two weeks and agreed not to sell any shell eggs to the public until the FDA completes its investigation and agrees to allow the companies to resume normal operations. The two companies supplied eggs that were sold under at least 25 brands.
In the meantime, the companies are selling their eggs to facilities that pasteurize them, a process that kills salmonella, and they will be used in liquid egg products or processed foods.
Christopher R. Braden of the Centers for Disease Control and Prevention said Thursday that the number of confirmed cases linked to the outbreak had increased by about 200 in the past week to 1,500 and that more cases are expected. Those figures do not reflect the number of people sickened by tainted eggs, because the CDC estimates that, for every case reported, about 30 are not. The outbreak is thought to have begun in May.
Salmonella enteritidis infections can cause nausea, vomiting, abdominal pain, diarrhea and fever. The illness can be briefly severe but is rarely life-threatening. In people with depressed immune systems, such as AIDS patients, salmonella can cause fatal bloodstream infections. No deaths have been reported in the ongoing national investigation.