Well, I remember reading that someone did tests on mice that were frozen vs fresh, and found that little to no taurine was lost during the freezing process, so the freezing thing does not concern me too much I think. I do wish I had saved where I read that though.
Heat and surface exposure are the true enemies of taurine.
With that being said, even with chunking the meat I kind of just pretend that there is pretty much none left in the food. I don't do that with the other vitamins that might be toxic, but since taurine is safely expelled, I don't worry that he is getting too much, as the consequences of too little are so severe. The product I linked is good for a person for 1 year, at 1000 mg per day. Obviously that is well over what cats need! I add 1/2 a tsp for every 3 lbs of meat mixture, as recommended by catinfo.org. Daily, I add just a pinch to his food, which is probably excessive, but I also worry that some of what I add to the mix depletes for whatever reason.
Consequently, dogs, particularly small dogs like I have, need taurine as well. I feed my cat and dogs the same mixture (I have tweaked the catinfo.org one to be better suited for dogs), so they benefit from the addition of taurine. Without it, they can start to have seizures.