Giving a series of network interviews in the wake of the egg and salmonella breakout, Hamburg said the FDA is taking the issue "very, very seriously." At the same time, she said Congress should pass pending legislation that would provide her agency with greater enforcement power, including new authority over imported food.
"We need better abilities and authorities to put in place these preventive controls and hold companies accountable," Hamburg said as she discussed the approximately 1,300 cases of salmonella poisoning and the recall of roughly a half-billion eggs from two Iowa egg distributors.
She also had some practical advice for consumers: Reject over-easy eggs. She said that as federal investigators continue their work with the companies involved, consumers should strictly avoid "runny egg yolks for mopping up with toast."
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Two Iowa farms linked to the disease outbreak - Wright County Egg and Hillandale Farms - share suppliers of chickens and feed as well as ties to an Iowa business with a history of violating state and federal law.
But, "It's complicated. There's many ways in which the eggs can become contaminated, whether it's environmental contamination on the farms, infection of the laying hens or feed that's contaminated," Hamburg told CBS' "The Early Show" Monday. "We're still working on the details of the, you know, initial source."
New FDA egg safety rules took effect in July, but the rules are tough to enforce completely for the 80 billion eggs produced in the U.S. each year.
"These new egg safety rules are very, very important," Hamburg said on "The Early Show." "Unfortunately, they went into effect a little bit after this outbreak began. But … these rules put in place for the very first time very rigorous and specific safety standards, so that we can hold companies accountable for compliance with important measures to reduce the risk of salmonella."
The number of illnesses, which can be life-threatening, especially to those with weakened immune systems, is expected to increase. The most common symptoms are diarrhea, abdominal cramps and fever eight to 72 hours of eating a contaminated product.
More on the egg recall:
Jewanna Porter, a spokeswoman for the egg industry, said Saturday the company Quality Egg supplies young chickens and feed to both Wright County Egg and Hillandale Farms. The two share other suppliers, she said, but she did not name them.
The egg industry has consolidated over recent years, placing fewer, larger businesses in control over much of the nation's egg supply to consumers.
The salmonella outbreak has raised questions about federal inspections of egg farms. The FDA oversees inspections of shell eggs, while the Agriculture Department is in charge of inspecting other egg products.
William D. Marler, a Seattle attorney for a person who filed suit alleging illness from tainted eggs in a salad at a restaurant in Kenosha, Wis., said Sunday his firm has been retained by two dozen families and was representing a woman who was hospitalized in California.
Businessman Austin "Jack" DeCoster owns Wright County Egg and Quality Egg. Wright County Egg recalled 380 million eggs Aug. 13 after it was linked to more than 1,000 cases of salmonella poisoning. A week later, Hillandale Farms recalled 170 million eggs.
DeCoster's companies have a long history of problems:
• In 1994, the state of Iowa assessed at least four separate penalties against DeCoster Farms for environmental violations, many of them involving hog waste.
• In 1997, DeCoster Egg Farms agreed to pay $2 million in fines to settle citations brought in 1996 for health and safety violations at DeCoster's farm in Turner, Maine. The nation's labor secretary at the time, Robert Reich, said conditions were "as dangerous and oppressive as any sweatshop." Reich's successor, Alexis Herman, called the state of the farms "simply atrocious," citing unguarded machinery, electrical hazards, exposure to harmful bacteria and other unsanitary conditions.
• In 2000,of environmental regulations for problems that included hog manure runoff into waterways. The label made him subject to increased penalties and prohibited him from building new farms.
• In 2002, the federal Equal Employment Opportunity Commission announced a more than $1.5 million settlement of an employment discrimination lawsuit against DeCoster Farms on behalf of Mexican women who reported they were subjected to sexual harassment, including rape, abuse and retaliation by some supervisory workers at DeCoster's Wright County plants.
• In 2007, 51 workers were arrested during an immigration raid at six DeCoster egg farms. His farms had been the subject of at least three previous raids.
• In June 2010, Maine Contract Farming, the successor company to DeCoster Egg Farms, agreed in state court to pay $25,000 in penalties and to make a one-time payment of $100,000 to the Maine Department of Agriculture over animal cruelty allegations that were spurred by a hidden-camera investigation by an animal welfare organization.
In a statement Sunday, Wright County Egg spokeswoman Hinda Mitchell said the company had reacted quickly in the past to correct its operations when "issues have been raised about our farms."
"We are approaching our work with FDA in the same forthright manner," she said.
The FDA investigation could take months, and sources of contamination are often difficult to find.
The CDC said last week that investigations by 10 states since April have identified 26 cases where more than one person became ill. Preliminary information showed that Wright was the supplier in at least 15 of those cases.
Hamburg appeared Monday on ABC's "Good Morning America," CBS's "The Early Show," and NBC's "Today" show.