Listeria
These food-borne bacteria can cause a rare infection called listeriosis. According to the FDA, an outbreak in 1985 in Los Angeles resulted in 142 cases of listeriosis including 46 deaths; 85 percent of the cases were Perinatal (pregnant women). The outbreak was traced to a soft, Mexican-style cheese, manufactured with contaminated milk (Jalisco cheese).
This infection causes mild flu-like symptoms in an adult, but can have a more dangerous effect on a fetus, and can cause stillbirth.
To be on the safe side, it may be advisable to avoid any raw or unpasteurized dairy product (such as raw milk), soft white cheeses such as brie, camembert, fresh blue cheese and Mexican white cheeses.
Also, Listeria can be found in hot dogs, bologna, and other pre-packaged luncheon meats. Reheating hot dogs to boiling temperatures is advised. (Reference: http://www.cfsan.fda.gov/~mow/fsislist.html)
Deli Meats
My advice is to buy freshly sliced deli meats rather than the mass-produced pre-packaged deli meats types sold in supermarkets.