Authorities (including FDA) and pharmacopeias (including USP) never establish quality of products!
Reasons:
(1) They do not define quality of the products, hence it cannot be measured and/or established (link).
(2) Suggested methods and procedures lack scientifically relevancy and validity (link)
(3) GMP practices, including inspections, are about operation of manufacturing not per se reflection of products quality (link).
