BACKGROUND: Chicken livers are regulated by the United States Department of Agriculture, Food Safety and Inspection Service (FSIS). Though pathogens have been shown to contaminate both the external and internal tissues of chicken livers, recipes recommending only partial cooking of chicken livers before consumption are widely available. Several recent illness outbreaks in the United States associated with chicken livers have been reported; however, limited data exist on the frequency and characteristics of such outbreaks. Common factors among chicken liver–associated outbreaks can inform foodborne illness prevention policy.
METHODS: Outbreaks during 2000–2015 associated with chicken livers were identified by reviewing data reported to FSIS’s Office of Public Health Science and the Centers for Disease Control and Prevention’s National Outbreak Reporting System to assess reported outbreak frequency and characteristics, including etiology, case-patient demographics and outcome, food preparation settings, and contributing factors.
RESULTS: During 2000–2015, 22 outbreaks of confirmed foodborne infection associated with chicken liver were reported in the United States. The average outbreak rate per year increased from 0.4 during 2000–2010 to 3.6 during 2011–2015; over half (12) of the outbreaks occurred during 2014–2015. Nineteen (86%) of the outbreaks were caused by Campylobacter and 4 (18%) by Salmonella (one was caused by both). The outbreaks resulted in a total of 331 reported illnesses (median of 6 illnesses/outbreak), 45 (14%) hospitalizations, and 0 deaths. Four (18%) outbreaks involved residents of >1 state. Undercooking of chicken liver was identified as a contributing factor in nearly all (20 [91%]) of the outbreaks. Most (19 [86%]) outbreaks were associated with food prepared in a food-service establishment (restaurant, residential care facility, religious facility, or school). Details about specific chicken liver dishes were reported for 16 outbreaks; comminuted chicken liver (pâté, mousse, or spread) was identified as a causative vehicle in all of these. In the largest outbreak (2011; Salmonella Heidelberg; 190 illnesses), the product was labeled “broiled” but was not fully cooked.
CONCLUSIONS: Outbreaks associated with chicken livers have been reported more frequently in recent years. Undercooked chicken liver pâté (and similar dishes) prepared at food-service establishments is a common feature of these outbreaks. Misleading labeling played a role in one large outbreak. Food preparers and consumers should be educated regarding the risks associated with consumption of undercooked chicken liver. Additionally, guidance should be given to chicken liver–producing establishments to reduce pathogen contamination and ensure proper labeling.