When you order an Italian cold cut sandwich from your local deli, you probably don’t expect to catch anything worse than a mild case of carb hangover. However, a new study from Purdue University, which tested meat samples from 30 local and chain delis from across the country, found that 9.5 percent of the tested samples contained listeria: dangerous and possibly lethal strains of bacteria that cause the foodborne illness listeriosis. [related]
The samples at each of the delis were tested over a six-month period, and bacteria were still found in most of the previously-affected samples over time, showing that listeria is persistent. Over the course of the study, only 30 percent of delis never tested positive for listeria.
According to the CDC, listeria, which causes 1,600 cases of foodborne illness nationwide annually (and kills one in eight people infected), the number of listeria cases are actually decreasing. However, listeriosis is still a serious problem: it is the most lethal of all common foodborne illnesses.
"We can't in good conscience tell people with weak immune systems that it is safe to eat at the deli," researcher Haley Oliver said in a press release. “This is a public health challenge.”