Do I need to include all of my suppliers under my purchasing procedure?

Do I need to include all of my suppliers under my purchasing procedure? Even things like cleaning supplies?

You are able to evaluate if purchases have an affect on quality of the product or service. Decide for each item purchased how important they are to the product or service, and determine what control you will need. Items that directly influence quality will need to come from suppliers that have been evaluated to determine that they can meet the quality requirements. Others may be purchased based on price or delivery concerns.