The Wright County Egg Farm in Galt, Iowa, announced a voluntary recall of 228 million eggs after they were linked to cases of salmonella poisoning around the country.
Nearly 300 cases of illness in California, Minnesota and Colorado have all been linked to the dangerous strain of salmonella, and health officials are now looking for links between the people infected by salmonella poisoning.
The eggs that are believed to be tainted were sold with 13 brand names: Lucerne, Albertson, Mountain Dairy, Ralph's, Boomsma's, Sunshine, Hillandale, Trafficanda, Farm Fresh, Shoreland, Lund, Dutch Farms and Kemp.
The egg cartons were packaged between May 16 and August 13 and stamped with one of three codes: P-1026, P-1413 or P-1946.
Consumers who believe they may have recalled eggs should return them to the store for a full refund, said the company.
The Centers for Disease Control and Prevention has estimated that the number of people sickened as a result of the salmonella outbreak could be in the thousands. During June and July, about 200 cases of the salmonella strain were reported weekly, four times normal levels.
"We're seeing a large increase in the number of cases of a particular type of Salmonella," said Dr. Chris Braden, a medical epidemiologist at the CDC. "It's pretty much blanketed the nation as far as we know."
The strain in question, Salmonella enteritidis, is particularly pernicious because it can affect the inside of an egg. The ovaries of a hen can be contaminated by the bacteria, passing the contaminant along to the whites and yoke of an egg as well as outside the shell, Braden said.
"The birds themselves aren't sick. The farmer doesn't even know what's going on. And in the meantime, it's producing eggs that look clean and fine," Braden said.
The federal government says its investigation into the source of the outbreak is ongoing, and while eggs are a prime suspect in many cases, other foods could also be involved. Officials have also not yet determined how salmonella got into the Iowa farm.
Woman Files Suit Over Outbreak at Wisconsin Restaurant
Already, one lawsuit has been filed in connection with an outbreak at a Kenosha, Wis. restaurant. A customer says she contracted Salmonella enteritidis there, and she's filed suit against both Wright County Egg and the restaurant, Baker Street Restaurant and Pub in Kenosha.
"Exactly how the salmonella came into the restaurant and whether there were cross-contamination issues in the restaurant or failing to cook within the restaurant, all of that is going to have to be worked out," said Bill Marler, the woman's Seattle-based attorney.
Outbreaks Across the Country Linked to Tainted Eggs
In northern California, officials noticed that dozens of people became sick after eating a certain kind of custard pie. In the southern part of the state, 12 people became ill after attending a catered event.
"It was traced back to the eggs they had consumed," said Dr. Angelo Bellomo of the Los Angeles County Department of Public Health. "At the same time we were doing this, similar incidents were being discovered in other parts of the country."
Egg Recall Latest in Line of Products Tainted by Salmonella Outbreaks
The U.S. Food and Drug Administration is still investigating the Iowa farm to try to find the source of contamination, though.
"Wright County Egg is fully cooperating with FDA's investigation by undertaking this voluntary recall," the company said in a statement. "Our primary concern is keeping salmonella out of the food supply and away from consumers."
Symptoms of salmonella-related illness could begin as many as three days after eating the eggs, and include fever, cramps and diarrhea, according to ABC News senior health and medical editor Dr. Richard Besser. Cooking eggs thoroughly greatly reduces the risk of salmonella poisoning.
Salmonella contamination was among the leading causes of foodborne disease outbreaks in 2007, with poultry, beef and leafy greens among the most common foods involved, according to the CDC.
Salmonella outbreaks accounted for 142 of the bacterial outbreaks in 2007, including two of the three largest, according to a report from CDC researchers in the Aug. 13 issue of Morbidity and Mortality Weekly Report. The outbreaks included 802 illnesses traced to tainted hummus, and 401 illnesses from frozen pot pies.
Rodents in food packaging and distribution facilities are the most common source of salmonella contamination.