With my first, I was so nervous about every little thing, I wouldn't touch deli meat unless I heated it first.
When I got pregnant with my second, I threw a lot of stuff out the window (deli meat rule, warm baths...) The chance of meat containing listeria, especially pre-packaged, is pretty slim. Think about it. Have you ever gotten sick from eating cold cuts before? If you have it probably calculates out to a <1% chance. That was my reasoning anyway. Not to mention, I craved turkey sandwiches like nobody's business when I was pregnant with my second.
All that being said, it's perfectly fine if you heat the meat to steaming first. I wouldn't have touched it with my first pregnancy, and I ate the crap out of it right out the fridge with my second. Never got sick. But like a previous poster mentioned, do what you're comfortable with.