I've come across recipes that involve the use of a Butane or Propane torch. Is it safe to use a propane torch bought at the Hardware store, or is there something different about the torches and/or fuel that is sold at a culinary store?
Propane and butane are pure alkanes. They don't produce anything nasty when burned. The worst you could possibly get should be carbon monoxide (and I am not even sure it can be produced in a torch, the dioxide ifs much more likely), but it being a gas, it won't stick to your food. The complex molecules you get from heating the food itself have more potential for being harmful than the combustion products of a propane butane torch. Ago yes, it is food safe.
Another matter of safety is that it is easier to cause a fire with a hardware store torch, because it has more power than the kitchen ones. But a sensible adult should be able to handle the thing safely.
You will achieve the exact same results and save yourself considerable money getting your propane torch at the local hardware store.
That said, depending on what you are attempting (Crème brûlée, for instance) may take some practice to get it right, but a generic propane soldering torch is fine.
Yes, you will be just fine food safety wise. The Bernzomatic heads available with the triggers are best for convenience. I actually recommend you look for MAP/MAPP gas which will lessen your risk of "torch-taste" but as was mentioned earlier the food safety issue is not a problem, it's the same propane that your grill uses.
A few tips, always start your torch facing away from your food. There will be a small puff of gas initially that you don't want to hit your food. Keep a nice blue hot flame and wave your torn like you were painting brush strokes on a canvas so you don't get hot spots.
I have worked in the metal industry with both products a map gas seems to me more of a mix of what we concidered waste gas where propane butane are as they said a clean burning natural gases I would use and think would be more safe for direct cooking. Also will get you out of a fix when you have left your lunch and have nothing more than a can of soup. Punchure the top and heat. Hell ive even cooked bbq shrimp for the whole crew with nothing more than aluminum foil and a rosebud hook to a propane tank. Got funny looks while doing it but a whole lotta thank you afterwards and when ya gonna do that again? ....."remember cooking is like sex more imagination you put into it the better it is".