Mapping the landscape of listeriosis outbreaks (1998-2023): Trends, challenges, and regulatory responses in the United States

Background: Listeria monocytogenes contamination in foods poses significant public health risks and economic losses, causing listeriosis. Scope and objective: This review synthesizes surveillance data on listeriosis outbreaks collected by food safety agencies in the United States during 1998-2023. It characterizes the shifting trends in implicated food categories, geographic distributions, and the evolution of related food regulations. Meta-analyses were conducted to delineate the death rate and hospitalization ratio of listeriosis outbreaks. Key findings: Data retrieved 129 foodborne listeriosis outbreaks, resulting in 1517 illnesses, 1191 hospitalizations, and 217 deaths. The pooled death rate and hospitalization ratio was 14% and 79%, respectively, lower than previous reported. Fresh produce, dairy, and meat-poultry products were the primarily associated food vehicles. Notable trends were observed in the shifting dominance of major food categories over time, corresponding with regulatory measures implemented by U.S. food safety agencies in the same period, prompting research focuses on controlling L. monocytogenes in specific foods. L. monocytogenes contamination primarily occurred in food processing facilities. While U.S. states with larger populations, more elderly residents, and higher birth rates had a greater total illnesses, states with smaller populations had relatively higher infection rates. Significance: This review provides insight into the key trends and characteristics of L. monocytogenes outbreaks in the U.S., contributing to a better understanding of foodborne listeriosis. It underscores the importance of ongoing research and collaborative efforts to mitigate L. monocytogenes contamination risks in foods.