Spokeswomen for the farms said the agents who arrived Tuesday worked for the Food and Drug Administration. Bob Teig, an assistant U.S. attorney for Iowa, and FDA spokeswoman Pat El-Hinnawy confirmed the presence of the agents, but neither would elaborate on what agency the agents work for or what they were doing there.
It is unclear whether this new investigation is the first step in a criminal probe. The FDA has jurisdiction to investigate crimes involving adulterated food, coordinating with the Justice Department.
The FDA concluded its investigation into the conditions of the farms Monday. Eggs from Wright County Egg and Hillandale have been linked to as many as 1,500 cases of salmonella poisoning, and the companies have together recalled more than half a billion eggs.
Austin "Jack" DeCoster, the owner of Wright County Egg, has paid millions of dollars in state and federal fines over the years for health, safety, immigration and environmental violations.
Hinda Mitchell, a spokeswoman for Wright, confirmed the presence of the FDA agents Tuesday. She said the company is continuing to cooperate with the government.
The reports released this week by the FDA show many different possible sources of contamination at both farms, including rodent, bug and wild bird infestation, uncontained manure, holes in walls and other problems that could have led to the outbreak. Positive samples of the type of salmonella linked to the illnesses have been found at both farms.
FDA officials said Monday they still cannot speculate on the cause of the outbreak but said the farms violated new egg rules put in place this summer.
No deaths have been reported due to the outbreak, but the number of illnesses — which can be life-threatening, especially to those with weakened immune systems — is expected to increase.
The federal Centers for Disease Control and Prevention has said this is the largest outbreak of this strain of salmonella since the start of the agency's surveillance of outbreaks in the late 1970s. For every case reported, there may be 30 that are unreported, the CDC said.
Thoroughly cooking eggs can kill the bacteria, but health officials are recommending people throw away or return the recalled eggs.