The new blog post from Gus Bassani, PCCA's chief scientific officer, explains "Why Brand and Generic Substitution Is Not the Same as Raw Material Substitution" — definitely worth a read.
You already know to get your ingredients from reputable repackagers and manufacturers, but Bassani explains that substitutability is a bit of a different creature. "USP specifications," he explains, "may not cover every important aspect of a raw material."
Check out the whole story.