Salmonella is to chickens as E. coli is to beef and Vibrio is to seafood. They are bacteria that are typically partnered with a particular animal or group of animals.
But did you know chickens have another bacterium that is actually more common than Salmonella? It’s Campylobacter. In fact, Campylobacter is the most common foodborne illness in the United States, according to the CDC’s April 2017 Morbidity and Mortality Weekly Report. A 2011 report from the CDC estimated that Campylobacter alone causes approximately 845,000 illnesses in the United States each year. In the United Kingdom, studies have found that 60% of tested chickens had confirmed Campylobacter colonization. Other studies have found Campylobacter contamination on up to 88% of chicken carcasses.
But have you ever heard of Campylobacter before? Until I became a food safety advocate, I never had.
Here’s a bit on this bug, and what you as a chicken caretaker need to know.
Campylobacter in a Nut(Egg) Shell, Pun Attempted
Campylobacter can be found in a wide range of environments – from sheep to water sources to pigs to birds. For the purposes of this article, we will discuss the fact that it colonizes the gastrointestinal tract of poultry. In fact, poultry seems to be the preferred host of this particular bacterium – which scientists believe is due to the birds’ higher body temperatures than other animals. Oftentimes, birds infected with Campylobacter do not appear to be sick – in fact, they may not show any symptoms. (As you know, some bacteria that make us sick do not make birds sick.) The good news, Campylobacter is in the intestinal tract, not the reproductive tract (which Salmonella can at times reside) or the muscle system.
So, what does this mean for us humans?
Testing has shown that any type of raw poultry could contain Campylobacter, including organic and “free-range” products. In fact, scientists from a 2002 Bristol University study found that organic and free-range birds were twice as likely to have positive Campylobacter colonization compared to indoor (commercial) flocks. The UK’s Soil Association believes this is “since organic birds are not treated regularly with antibiotics, they are likely to carry more bugs.” But there could be another reason. Organic birds are grown more slowly than commercially-raised birds –which are typically fattened up for slaughter in only about 42 days. The fact that organic and free-range birds have a longer lifespan, which may them more time to become infected than commercial birds.
How Contamination Occurs
Well, people become infected with Campylobacter through the consumption of contaminated poultry meat. Although the muscles in a chicken may be sterile, they can become contaminated during the slaughter process. Bacteria from the digestive tract, lungs, skin, feathers, and outside vectors (like fecal matter or human contamination) can later cross-contaminate onto the chicken meat.
However, contamination usually begins during transportation to slaughter. It is rare that only one bird is transported to a poultry processor at a time. So, as chickens are transported, they do as chickens do – poop. These feces get onto the feet and feathers of other chickens around them. Hence, contaminating other chickens around them.
But that isn’t the only way. If you know anything about chicken processing, you know what de-feathering a bird is rarely done by hand anymore. Feather plucking machines put pressure on the processed birds during the de-feathering process. This can cause fecal matter to be pushed out of the bird’s carcass onto the equipment. This means other birds that will be processed and de-feathered using the same machine will also become contaminated.
How Can the Chicken Farmer Help Out?
As those who raise chickens, there is a lot a chicken farmer can do to help reduce the risk of Campylobacter spread. The first (and best) thing is to keep a clean coop and ensure the clean transport of birds for processing.
