Listeria Monocytogenes: a Continuing Challenge

As a leading cause of death from a foodborne pathogen, Listeria monocytogenes continues to cause sporadic cases and outbreaks of illness. The most recent of these outbreaks in the United States involved consumption of hot dogs, with 101 cases of illness and 21 deaths reported to the Centers for Disease Control and Prevention for the years 1998-1999. Epidemiologic analysis determined that contamination levels in hot dogs were remarkably low (0.3 CFU [colony-forming units] L monocytogenes serotype 4b/g). That same year, manufacturers of hot dogs and luncheon meats collectively recalled more than 500,000 pounds of product owing to possible Listeria contamination. This article, through focus on issues such as reexamination of zero-tolerance policies, improvements in detection and enumeration procedures, the impact of epidemiologic innovations, and measures needed to further reduce the incidence of listeriosis will highlight why L monocytogenes remains a continuing challenge for the food industry.