The Prevalence of Campylobacter in Food and Elsewhere
How prevalent is Campylobacter food contamination?
Campylobacter infection is commonly associated with the consumption of raw (unpasteurized) milk, undercooked poultry, and contaminated water; however, most Campylobacter cases are sporadic and are never traced back to a specific food or beverage. Because of this, historically, very few foods have been recalled due to the presence of Campylobacter bacteria.
From 2007-2012, Campylobacter was the pathogen responsible for illness in 62 outbreaks associated with raw milk, making it responsible for 81% of all such illnesses during the five-year span. The source of Campylobacter contamination of raw milk is likely cattle feces, although inoculation of the milk may also occur directly as a result of bovine mastitis.
Aside from the consumption of contaminated milk, since 1992, other food products remain the most common vehicle for the spread of Campylobacter, and chicken is the most commonly implicated. As one authority points out, “commercially raised poultry is nearly always colonized with C. jejuni, slaughterhouse procedures amplify contamination, and chicken and turkey in supermarkets, ready for consumers to take home, frequently is contaminated.”
A United States Department of Agriculture (USDA) Baseline Data Collection Program done in 1994 documented Campylobacter contamination on 88.2% of broiler-chicken carcasses. Subsequent USDA data collection showed an estimated 46.7% prevalence of Campylobacter in chicken and 1.46% in turkeys. Retail chicken testing performed by the National Antimicrobial Resistance Monitoring System (NARMS) suggests that prevalence of Campylobacter in chicken has declined, noting a decrease from 60% in 2004 to 24% in 2015. Recovery of Campylobacter in the aforementioned 2015 NARMS study was lowest in poultry and highest in bovine and swine cecal (intestinal) samples. Campylobacter is also prevalent in wild birds of all kinds.
With poultry, contamination levels peak during the summer months, and this seasonal pattern is reflected in the number of reported Campylobacter infections. One poultry product that has gained more attention recently related to Campylobacter infection is chicken livers. Twenty-eight outbreaks were attributed to chicken livers from 2000 to 2016, 89.2% of which were caused by Campylobacter. Although chicken livers are recommended to be cooked to the same internal temperature as whole or ground muscle poultry, they are often served undercooked in dishes such as pâté.