The next time you feel the urge to grab sliced cured meats from your local grocer or order a deli sandwich for a quick hunger fix, you might want to rethink your purchase.
Retail cold cuts might still come with deadly Listeria pathogen according to a study from Purdue University. Actually, Listeria pathogen remains prevalent and persistent in retail cold cuts or deli meats despite observance of standard cleaning procedures.
Haley Oliver, assistant professor of food science at Purdue University, led the study and found that 6.8% of samples taken in 15 delis before daily operation had tested positive for L. monocytogenes bacteria. A second sampling found that 9.5% of samples from 30 delis during operation over six months tested positive for the same pathogen. Again, in monthly samplings involving 12 delis, L. monocytogenes was present.
Note that the samples were taken by swabbing several surfaces that were further categorized into two—those surfaces that came in direct contact with meats such as slicers and counters, and those surfaces that usually do not come in contact with food such as floors, drains, and squeegees. Although most of the positive samples came from “indirect” surfaces, Oliver reminded that the bacteria could be transferred unknowingly to food or meat.
“This is a public health challenge,” Oliver said. “These data suggest that failure to thoroughly execute cleaning and sanitation protocols are allowing L. monocytogenes to persist in some stores. We can’t in good conscience tell people with weak immune systems that it is safe to eat at the deli.”
Listeria or specifically, the L. monocytogenes pathogen can cause common food poisoning symptoms such as diarrhea. The infection is serious but transient. However, for immunocompromised people including infants, children, pregnant women, the elderly, or those with HIV, the pathogen can cause listeriosis, especially if it passes through several barriers such as intestinal membrane, thus entering the blood stream, blood-brain barrier, and placental barrier.
Listeriosis is a serious and potentially fatal bacterial infection affecting the central nervous system. Specific derivative illnesses include meningitis, meningoencephalitis, brain abscess, and cerebritis.
Cold cuts or ready-to-eat deli meats are prone to L. monocytogenes contamination because the bacteria can grow at refrigerator temperature unlike Salmonella and E. coli.
Although there are stringent measures and inspections implemented at meat processing plants that eventually lessened the risk of listeria contamination, there are no similar and appropriate measures and inspections performed at retail stores. Several risk assessments revealed up to 83 percent of listeriosis cases linked cold cuts consumptions are attributable to products retail-specific contamination.
Oliver mentioned that standard sanitation operating procedure in delis could keep the listeria bacteria at bay, particularly if the establishment is in top condition. Sanitation, however, is almost impossible in establishments with structural damages such as clogged drainage, loose wall coverings, and missing grout.
For immunocompromised consumers, Oliver advised that they should instead by prepackaged deli meats or opting for ready-to-eat cold cuts, they should heat it to 165 degrees. She reminded that meats contaminated with L. monocytogenes do not show signs of spoilage such as odor or sliminess.
Photo credit: Purdue University/Tom Campbell