My advice? Use your keyboard for whatever you want. If you need to smack someone in the mouth with it on your way out of the office after being fired, smack away. You'll probably lose a few keycaps, though.
For defense against zombie bites, I'd recommend a Model M, however. Especially the models with the channel openings in the case, which will allow the blood and bile to run right out from the barrel plate and not accumulate in the keyboard.