There are five words that no one in the food industry ever wants to hear—Listeria positive in finished product. Normally, I would not start a communication with this type of dramatic statement. But, the recent outbreaks of Listeria and the tragedy of foodborne illness fatalities provide impetus to emphasize the importance of this pathogen.
Listeria is a relatively well-known genus of Gram-positive, rod-shaped bacteria that includes a major human pathogen, Listeriamonocytogenes. The genus also includes L. ivanovii, which is primarily an animal pathogen, as well as L. innocua, a potential opportunistic Listeria species that is often characterized in the food industry as a Listeria “indicator” organism—crucial in “indicating” when a potentially dangerous situation exists. To put it more simply, there is a justifiable zero tolerance mindset for ANY confirmation of a Listeria spp. in a food production or distribution facility.