Legionella in the Grocery Store: Assessment of Risk

An outbreak of Legionnaires' disease is associated with a grocery store mister/fogger machine occurred in Louisiana in 1989. Since mister machines are used in many industrial settings, there is a need for the food industry to become better acquainted with this problem. Legionella, the causative bacterium of Legionnaires' disease and Pontiac fever, was first discovered in a 1976 outbreak in Philadelphia, but is known to have caused disease as early as 1943. Once considered exclusively an American disease associated only with air conditioning, outbreaks of Legionnaires' disease have occurred worldwide, and most recent outbreaks have been traced to breathing bioaerosols from potable water sources. There are 30 known species of legionellae bacteria and 48 serogroups. The bacteria are widespread in natural water environments and may be amplified in plumbing and cooling systems in buildings and industrial settings. The presence of legionellae bacteria does not always represent a health risk but systems which amplify the bacterium in water and disseminate the bacteria in the form of bioaerosols should be conrolled.