It really depends on your own risk assessments of the materials you purchase what you require and what food quality standard you have, eg BRC, SQF etc.
Food quality standards require you to have a documented procedure for the acceptance of packaging and raw materials of which the acceptance is based on a risk assessment of these materials.
The BRC standard gives you an option of one or a combination of methods to determine acceptability of receipt and use of your raw materials and packaging.
Sample and testing.
Inspection at receipt
COA
COC
If you have completed your material risk assessments you should already have your own requirements. You should have on file at a minimum, your vendors own product specifications. You'll need these specifications to compare any of your own analysis or COA/COC results against the specification parameters you have on file (providing the COA's do not already record the parameter limits.) It's a sanity check as well as some vendors can change their limits and neglect to tell you. They can also send you materials that are out of specification without telling you. Yes this does happen and has happened to our business a few times!
Depending on the complexity of the product you can be provided with a COC - certificate of conformance which basically means that the product will meet the product specification. Salt for example is only ever provided to us with a COC. The vendor could provide a COA - certificate of analysis, which means the product has been tested/checked and released against the specification and the results report will align with the limits set in the agreed to the vendor specification.
The GFSI food quality standards always has some requirement for a procedure to be in place for raw material and packaging acceptance monitoring. The decision is up to you how you want to check your incoming raw materials but you have to have something in place if you want to meet the GFSI quality system requirements.