Recently there has been a marked increase in regulatory citations concerning the adequacy of suppliers. It bodes well to pay particular attention to what is listed in your URS, when auditing a potential supplier, just to make certain that all specialist tasks are within the subcontracts capabilities and facilities.
Possibly the reason for this increase is the fact that audits are often very poorly documented. Since audits are a GMP requirement, the regulators have a right to review them; this of course means it is essential to develop a good audit document
Extract from warning letter.
7. You failed to evaluate and select potential suppliers on the basis of their ability to meet specified requirements [21 CFR 820.50(a)(I)],