The Food and Drug Administration (FDA or USFDA) is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments.
The FDA is responsible for protecting and promoting public health through the regulation and supervision of food safety, tobacco products, dietary supplements, prescription and over-the-counter pharmaceutical drugs (medications), vaccines, biopharmaceuticals, blood transfusions, medical devices, electromagnetic radiation emitting devices (ERED), veterinary products, and cosmetics.
The FDA makes sure that safe and effective drugs are available to improve the health of patients who need them. The FDA evaluates new drugs before they can be sold and ensures that prescription and over-the-counter drugs, both brand name and generic, work correctly and that the health benefits outweigh known risks. The FDA’s review of new drug applications not only prevents unsafe drugs from entering the market, but it provides doctors and patients with the information they need to use medicines wisely.
In addition, the FDA continues to actively monitor and ensure the safety of drugs after approval. Among its post-marketing activities, the agency analyzes reports of adverse reactions submitted by companies and health care practitioners, and in some cases requires pharmaceutical manufacturers to conduct additional post-marketing testing (Phase IV trials) to evaluate long-term effects of approved medicines.
As this is the role of the FDA, I would say that the FDA determines the standard of quality for a product, at least as it pertains to the safety, quality, efficacy, identity, potency and purity. However, it is through regulations that the company is expected to prove its product(s) are safe and effective and to maintain this through each batch / unit.
In brief, the company determines the standard of quality for their product based on systems / processes put in place as a necessity to meet the regulations established by a regulatory body agency (i.e. FDA). This is of course after acceptance by the agency of the submitted license to manufacture that product. It is the burden of proof upon the company to demonstrate that the product was manufactured in a consistent manner, while meeting the criteria for a safe, effective, pure, potent product. As it is the FDA’s role to ensure safe and effective products are on the market, the ‘customer’ doesn’t have the choice to accept the product with less quality.