I think a better point to this would be to say that CI requires some periodic maintenance and porcelain does not. I don't get any off tastes from my CI because I use it regularly and keep it seasoned. If you don't, you will get off/rusty tastes. Porcelain requires no maintenance, but its limited in durability when compared to CI. Both have their strong and weak points, but the housing bacteria point is moot because it gets cooked off anyway. Besides we prolly eat more bacteria just from kitchen surfaces alone than you'd find in a CI pan.