Salmonella in Eggs
Salmonella is a pathogenic bacteria that causes foodborne illness and is often found in eggs. One of the most famous outbreaks of illness caused by Salmonella was the 2010 outbreak of salmonella from eggs linked to Austin "Jack" DeCoster. According to a 2009 report by the U.S. Food and Drug Administration,
- "Most types of Salmonella live in the intestinal tracts of animals and birds and are transmitted to humans when animal feces contaminate a food item of animal origin (such as eggs). Regulations for cleaning and inspecting eggs were implemented in the 1970s and have reduced salmonellosis caused by external fecal contamination of egg shells. However, Salmonella enteritidis, the most prevalent type of Salmonella in eggs today, infects the ovaries of otherwise healthy hens and contaminates the eggs before the shells are formed."
The 2009 report found that half of all egg outbreaks occurred from restaurants and other food establishments. The largest egg outbreaks occurred at prisons and catered events were also a large cause of outbreaks. They note that "while proper egg handling and cooking should destroy most pathogens, serving eggs raw or “runny,” or leaving egg dishes at improper holding temperatures (such as on a breakfast buffet) can allow the bacteria to multiply."
In 2010, food writer Barry Estabrook speculated that his own backyard hens would be free of salmonella, compared to eggs from hens in large, confinement operations. He sent a dozen of his own eggs for testing and they tested negative for salmonella. Upon investigating the results, Estabrook found the following:
- "One explanation for why my eggs were Salmonella-free might have been that the odds to begin with were highly in my favor. Even in areas of high contamination, only one egg in 10,000 will become infected because infected hens shed the bacteria intermittently, according to Patrick McDonough, a bacteriologist at Cornell University’s veterinary school. McDonough added that my chickens probably arrived at my coop from the hatchery as healthy chicks and had never been exposed to the bacteria.
- "Another reason might be that raising chickens under a free-range system makes them less susceptible to salmonella. “I don’t think there is any doubt about it that healthy chickens living in decent surroundings are just going to be a lot more resistant to salmonella,” said John L. Ingraham, emeritus professor of microbiology at the University of California Davis, and author of the book March of the Microbes, recently published by Harvard University Press. “Take any creature, ourselves included, you put them in a terrible stressful conditions and they become susceptible to disease.”
- "Ingraham, who happens to maintain 13 laying hens, also suspects that the massive doses of antibiotics fed to confined farm animals could be a factor in the spread of Salmonella. “Antibiotics kill off healthy, normal intestinal flora. That gives salmonella a good chance to get started there,” he said.
- "Recent studies of hens in France and Great Britain confirm that birds that are allowed to roam are less likely to get salmonella than those kept in confinement.
- "Ingraham has no qualms about making traditional Caesar salad dressing and mayonnaise—both of which involve uncooked eggs—with eggs from his own flock. “I’d be afraid to do that with a supermarket egg,” he said."
Resources and articles
Related Sourcewatch articles
- Salmonella (Wikipedia)
- The 10 Riskiest Foods Regulated by the U.S. Food and Drug Administration, Center for Science in the Public Interest, 2009
- , Barry Estabrook, "Why Free-Range Hens Might be Less Susceptible to Salmonella than Their Factory-Farmed Sisters: Results from the Great Egg Challenge of 2010," Politics of the Plate, September 21, 2010, Accessed October 9, 2011.
- CDC Estimates of Foodborne Illness in the United States
- Foodborne Disease Outbreaks Are Deadly Serious – What You Can Do to Avoid Them, CDC.
- Surveillance for Foodborne-Disease Outbreaks --- United States, 1998--2002," Centers for Disease Control and Prevention
- Surveillance for Foodborne Disease Outbreaks --United States, 1993-1997," Centers for Disease Control and Prevention
- Foodborne Disease Outbreak Surveillance, Centers for Disease Control and Prevention