This whole thing is very scary. My mom's little malti/poo has been on Fromm from the time she was a puppy. I just got a new puppy myself and the breeder was feeding her Purina Pro Plan. I was going to transition her to a better grade food but now I am scared to do that. There is a Facebook group that is discussing all these issues with DCM. They even have tables of all sorts that you can look at showing which dogs were affected and which foods were being used etc. I only had a little time to skim through it as the new puppy is monopolizing my time. Here is the link if you are interested:
https://www.facebook.com/groups/TaurineDCM/
https://www.facebook.com/groups/TaurineDCM/