Salmonella Risk Linked with Backyard Chickens

A six-month study by researchers at Penn State’s College of Agricultural Sciences confirms information from the FDA and CDC that eggs from both large and small flocks of chicken can be contaminated with Salmonella enteritidis.

The CDC has reported that eight multistate outbreaks of human Salmonella infections have been linked to live poultry in backyard flocks during the first nine months of 2016: 895 people have been infected in 48 states, including 209 hospitalizations and three deaths; 254 of the illnesses have been among children 5 years of age or younger. This is the largest number of illnesses linked to contact with backyard poultry ever recorded.

Subhashinie Kariyawasam, PhD, microbiology section head at Penn State’s Animal Diagnostic Laboratory, and colleagues purchased two to four dozen eggs from each of 240 randomly selected farmers markets or roadside stands representing small layer flocks in 67 Pennsylvania counties. The researchers cultured separately the internal contents of the eggs and eggshells for Salmonella using standard protocols. Two percent of the eggs tested positive for the pathogen, a higher prevalence than has been found in studies of eggs from large flocks of 3,000 birds or more.

Dr. Kariyawasam presented their research at the recent meeting of the American Veterinary Medical Association and the American Association of Avian Pathologists. The research, she says, “highlights the potential risk posed by the consumption of eggs produced by backyard and small layer flocks.” The analysis of the Salmonella enteritidis showed that the pathogens were the same type commonly reported to the CDC from human foodborne outbreaks, she says.

The FDA guidance for prevention of Salmonella enteritidis applies to egg producers with flocks larger than 3,000 laying hens. Among the prevention measures spelled out in the rule are ones limiting visitors on the farm and in the poultry houses, and preventing stray poultry, wild birds, cats, and other animals from entering the poultry houses. These prevention measures include three basic components: isolation, traffic control, and sanitation. The egg rule requires intensive monitoring for rodents and flies, removal of manure, continuous testing from any Salmonella-positive poultry house, and other regulations.

These regulations, however, do not apply to backyard hens or small flocks. The FDA advises that backyard chickens, ducks, and other poultry, even those organically fed, commonly carry Salmonella, meaning that humans who handle these birds and eat their eggs may be exposed to the pathogen. The FDA and the CDC offer prevention advice for people who keep backyard chickens: handwashing immediately after touching poultry; washing clothes after contact; not drinking or eating in the area where birds live or roam; prohibiting children younger than 5 years or adults older than 65 or people with weakened immune systems from handling or touching chicks, ducklings, or other live poultry; not snuggling or kissing the birds; and not consuming raw or undercooked eggs.