The deadly Listeria monocytogenes outbreak linked to deli sliced meats and cheeses that was announced yesterday by the CDC has sickened eight people and one Michigan resident has died. For years, Food Poisoning Bulletin has told you about dozens of recalls of deli items for possible Listeria contamination. Why are these deli sliced products vulnerable to Listeria?
Listeria monocytogenes is a very persistent and strong pathogen. It is found in the air, water, soil, animals, and plant material. Once it has been introduced into a facility, especially a moist and cool environment, it can become established and be very difficult to get rid of. The pathogen can hide in floor cracks, grease traps, air vents, in machines and surfaces that are difficult to clean, on food preparation surfaces, and in drains. The pathogen can move around the facility on food carts, on employee’s feet, and through cooling fans.
A CDC study conducted on retail deli slicer cleaning methods found that most establishment did not clean their meat and cheese slicers often enough, which could cause contamination. Some deli managers interviewed in that study did not know that the slicers needed to be disassembled to clean them properly. If a slicer is used to slice meat, for instance, that is contaminated, any other food prepared on that slicer could be contaminated as well.
Another study found that Listeria monocytogenes bacteria can survive standard cleaning procedures used by many delis. Researchers found that many of the floors, drains, and squeegees in deli locations harbored the pathogen. While those surfaces don’t come into contact with food, the bacteria could be transferred to the food unintentionally. The study also found that from 6.8 to 9.5% of food samples taken from delis were positive for Listeria monocytogenes.
And, unfortunately, Listeria monocytogenes is one of the few pathogens that can grow, albeit slowly, at refrigerator temperatures, which usually inhibit bacterial growth. Freezing does not kill this pathogen. That means that even if the meats and cheeses are properly refrigerated, Listeria will still grow.
Food safety attorney Fred Pritzker, who has represented many clients sickened with listeriosis, said, “Because these deli sliced products are usually eaten without heating them, the classic ‘kill step,’ people will get sick if deli cheeses and meats are contaminated with the pathogen.”
There aren’t many Listeria monocytogenes outbreaks in the United States every year. The pathogen causes about 1,600 illnesses every year; most are isolated cases. But when someone is sickened with this bacteria, they usually get very sick. Every person sickened in this outbreak has been hospitalized.
The symptoms of listeriosis include high fever, stiff neck, severe headache, nausea, and diarrhea. Pregnant women, who could suffer stillbirth or miscarriage if they contract this infection, may only have a mild illness that is similar to the flu.
Since the outbreak information is scarce, if you or someone you know has eaten meats or cheeses from a deli and has been sick, see your doctor. You may be part of this Listeria monocytogenes outbreak. People who have been sickened in this outbreak live in Pennsylvania, New York, New Jersey, and Michigan.