21 CFR § 117.420 - Using approved suppliers.
(a) Approval of suppliers. The receiving facility must approve suppliers in accordance with the requirements of § 117.410(d), and document that approval, before receiving raw materials and other ingredients received from those suppliers;
(b) Written procedures for receiving raw materials and other ingredients.
(1) Written procedures for receiving raw materials and other ingredients must be established and followed;
(2) The written procedures for receiving raw materials and other ingredients must ensure that raw materials and other ingredients are received only from approved suppliers (or, when necessary and appropriate, on a temporary basis from unapproved suppliers whose raw materials or other ingredients are subjected to adequate verification activities before acceptance for use); and
(3) Use of the written procedures for receiving raw materials and other ingredients must be documented.