Frying temperatures are usually above 300 degrees F. Any simering is done around the boiling temperature of water, around 212. The harmful bacteria found in food begins dying off at around 140 and is long dead at 160. So, unless you are using your cast-iron to serve cold foods, you lon't have to worry much about bacterial contamination from frying chicken, then the veggies from a stir-fry, for instance.
In addition, cast iron is as easy, or easier to maintain than is teflon. It will withstand greater temperatures (I've had mine up to 550) is not prone to damage from metal utensiles, and if seasoned initially, is as easy to clean as is teflon. The only down side is that soap will disolve the grease coating, resulting in the need for re-seasoning. But I just use hot water and a stiff-bristle scrub brush and cleaning is nearly effortless. That's not to say that I haven't abused my pans and made things stick to them. But even then, they are salvagable with a bit of elbow grease. Do the same thing to teflon and you might as well throw away the pan.
I am a huge fan of cast-iron. I like stainless with encapulated bottoms, or fully clad too. But more things get cooked in my cast iron than in any other pan type I own. I even use them for baking, broiling, and roasting chores. As a bonus, you can throw them on two good logs of a campfire without damaging the pan.
Seeeeeya; Goodweed of the North