What is the difference between a product specification and a certificate of analysis?

The specification defines the agreed acceptance criteria for the product—such as identity, physical attributes, nutrient or active ranges, microbiological limits and packaging requirements. A certificate of analysis reports results or confirmations for a particular batch against those criteria. Buyers should agree which tests are performed per batch, which are verified periodically and which methods apply. A COA should be traceable to the product code, lot and manufacture or release date; it should not be treated as a general marketing certificate.