OK, I just did a google search to figure out what this alphabet soup meant.

SRM's are Specified Risk Material of carcasses. I found this report from Canada which banned SRM's from dog food after a case of Mad Cow Disease. I didn't read all of it, or all of the thousands of "hits" I got in google. But this may help.

http://www.petprofessional.ca/featur...feature03.html

The proposal is to ban SRM's from "all animal food including pet food." I guess that means SRM's currently go into farm animal foods too.

Should you use Merrick? Beats me! Can you even find another dog food which voluntarily does not use SRM's? I'm not sure how you would go about that, as I don't know if the labels SAY "SRM's used."

Hope this gives you some help.