September 25, 2010
Last week, Austin J. DeCoster, one of the country’s biggest egg farmers, was asked by a Congressional committee how eggs from his Iowa farms had sickened thousands of people nationally with a bacterium called Salmonella enteritidis. His answer: “This is a complicated subject.”
More than half a billion eggs were recalled last month, the majority from a group of Iowa farms, called Wright County Egg, owned by Mr. DeCoster. It is not the first time that eggs he produced made people sick. He has sold eggs that caused salmonella outbreaks several times before, including a 1987 outbreak at a New York City hospital in which about 500 people got sick and 9 died.
All that has many people looking askance at the eggs in the supermarket and wondering what is safe.
Should consumers just buy organic or local eggs? Are they safer?
“There’s no science that says that they are,” said Carol Tucker Foreman, a food safety expert at the Consumer Federation of America. “People note you don’t have big outbreaks associated with locally sourced food, but that’s generally because it serves far fewer people.”
In any case, the Food and Drug Administration’s new egg safety rule, which went into effect in July, after the current outbreak began, applies only to large operations with at least 50,000 hens. (In 2012, it will expand to include farms with at least 3,000 hens.) That means that smaller operations are not required to put in place the same safeguards, like rodent control measures.
The case for cage-free eggs is also subject to debate. Some scientific studies, mostly conducted in Europe, have found lower salmonella rates in flocks of cage-free hens, compared with hens living in cages. But that could be explained by the fact that the cage-free henhouses in the studies were often newer and less likely to harbor the rodents that can spread salmonella.
Why have no deaths been reported in the current outbreak?
A big reason is that the deadly outbreaks in the past often occurred in nursing homes or hospitals, where the bacteria attacked the elderly or infirm. After several deaths in the late 1980s, nursing home and hospital kitchens largely switched to pasteurized egg products.
How does salmonella get into the eggs anyway?
The bacteria infect the laying hens but do not make them sick, so they show no symptoms. Bacteria can then enter a bird’s ovary or oviduct, where they can infect the egg as it is formed. But that’s rare, and even in those cases, only a small number of eggs will be laid with the bacteria inside.
How did this problem start?
Salmonella enteritidis in chicken eggs mysteriously began to appear in many countries at about the same time in the late 1970s and early 1980s. One theory, by Andreas J. Bäumler, a microbiologist at the University of California, Davis, ties the bacterium’s emergence to the virtual eradication of two related strains of salmonella that make chickens sick. Once those strains were stamped out, through culling of infected birds, the theory goes, immunity to similar strains of salmonella decreased. That opened up a niche for enteritidis to thrive.
How difficult is it to get rid of salmonella on egg farms?
Vaccination of the birds has been very effective. In England in 1997, a severe salmonella epidemic convinced most egg farmers to vaccinate, and today, most eggs sold in England and Wales come from vaccinated hens. Salmonella illness from eggs there has almost been eliminated. But farmers must also be aggressive in controlling rodents, the most common route to infection in hens. Henhouses must be rebuilt or refurbished, and basic sanitation is essential.
How often are egg farms inspected?
Many egg farms have processing plants where the eggs are washed, sorted and packaged. These plants are inspected regularly, even daily, by the United States Department of Agriculture. But those inspectors are checking to make sure that equipment is clean and that eggs don’t have cracks or are sorted properly. They do not go into henhouses, which have largely been ignored by government inspectors. In response to the outbreak, the F.D.A. says it will inspect each of the approximately 600 large egg farms in the country by the end of next year.
Salmonella enteritidis has been a problem on Mr. DeCoster’s farms for years. Can’t he be charged with a crime?
Criminal charges in food-poisoning cases are rare, according to Bill Marler, a Seattle lawyer who has represented many people sickened by toxic bacteria in food. To send someone to jail, he said, prosecutors must prove that the person knew that the eggs would sicken people. That is not easy to prove. Although tests showed that salmonella was present in the Iowa henhouses, that does not mean the bacteria will be inside the eggs. Mr. DeCoster could argue that he could not have known his eggs were contaminated.
I love fried eggs with runny yolks, and soft scrambled eggs. Do I have to give them up?
Scientists believe that under normal conditions, only a tiny fraction of eggs contain salmonella. Even so, the F.D.A. estimates that 142,000 people a year fall sick from salmonella in eggs. In this outbreak, many who have fallen ill contracted the salmonella at a restaurant, often by eating dishes that contained eggs, like a pastry with a filling made from raw eggs. Restaurants are more likely to break and mix together large numbers of eggs, which creates a situation where bacteria in a single egg can multiply and contaminate many more.