I switch between TOTW salmon and the sierra mountain (lamb) formula. I saw some things about ethoxyquin (which is probably what your breeder was talking about) when I was researching what food to get, and this is what the TOTW website has to say (from the FAQ section):
Does this food contain ethoxyquin?
Taste of the Wild Pet Foods sources all protein meals (chicken meal, fish meal, etc) from vendors that do not use ethoxyquin. As always, only natural preservatives are used in our manufacturing process to preserve the foods.
Mansa does pretty well on this food. I switched from costco food that was giving him digestive issues, probably because of the grain content. Hopefully there are no widespread problems with the TOTW food. Its so frusterating when you as the consumer can't trust that what you are giving your dog is the best for them.