Nearly 1 in 10 samples from delis carried the dangerous bacteria, researchers say
WebMD News from HealthDay
By Robert Preidt
HealthDay Reporter
WEDNESDAY, Feb. 11, 2015 (HealthDay News) -- The next time you order that pastrami-on-rye at your local deli, you may get an unwanted ingredient -- the illness-inducing listeria bacterium.
That's the finding from a Purdue University study of dozens of delicatessens. Researchers say that on any given day, up to one in 10 deli swab samples tested positive for the Listeria monocytogenes germ.
"This is a public health challenge," study leader Haley Oliver, assistant professor of food science, said in a university news release.
"These data suggest that failure to thoroughly execute cleaning and sanitation protocols is allowing L. monocytogenes to persist in some stores," she added.
While listeria infection can cause serious but transient gastrointestinal illness in most people, the Purdue team noted that foodborne illness is potentially deadly in people with weakened immune systems. Those people include the elderly, infants and small children, and people living with HIV.
"We can't in good conscience tell people with weak immune systems that it is safe to eat at the deli," Oliver said.
In the study, Oliver's team first collected samples from 15 delis before they opened for the day. They examined swab samples from deli surfaces that came into contact with meat (such as slicers or countertops), as well as surfaces that did not, and found that nearly 7 percent of the samples tested positive for listeria bacteria.
A second round of testing at 30 delis over six months found that 9.5 percent of the samples tested positive for the bacteria. In 12 of the delis, the same subtypes of the bacteria were found in several of the monthly samplings. This suggests that the bacteria can persist in certain areas over time, the researchers said.
Only about 30 percent of delis never tested positive for listeria over the course of the study. But in some of the delis, samples came back positive for listeria about 35 percent of the time.
In most cases, positive samples came from surfaces that aren't usually in contact with food -- for example, floors, drains or squeegees. But the researchers noted that it's still easy to transmit the bacteria from these surfaces to a surface that's likely to touch food.
source : Your Deli Sandwich May Come With a Side of Listeria, Study Finds
