People get confused because everyone's Dr tells them something a little different. Personally my Dr says I can eat lunch meat every now and then without heating it.
"Listeriosis is an uncommon foodborne illness caused by Listeria monocytogenes. Pregnant women are particularly susceptible to the disease, which can result in fetal death or chronic intrauterine and congenital or perinatal infection. Investigation of symptoms such as headache, myalgia and fever associated with relatively inconspicuous gastrointestinal symptoms in a pregnant woman should include a recent dietary history and blood culture. It is treatable with penicillin."