Let's see if I can take a stab at it.
The definitions of CCP and Preventive Control are essentially the same. A Preventive Control prevents or significantly minimizes a hazard. A CCP eliminates or reduces a hazard to an acceptable level.
The differences may seem small, but they are the essential difference between a HACCP Plan and a Food Safety Plan. HACCP Plans are predicated on pre-requisite programs that are supposed to reduce hazards, and then any hazard that remains, is essentially a CCP.
Food Safety Plans assume no pre-requisite programs when conducting the hazard analysis and risk assessment.
Process Preventive Controls are linked with a particular point in the process or a particular piece of equipment. They do not fit into the other groups of Preventive Controls. (Sanitation Preventive Controls, Supply Chain Preventive Controls, and Allergen Preventive Controls)
Process Preventive Controls should be managed the same as CCP's.
Sanitation, Supply Chain and Allergen Preventive Controls are not necessarily "CCP's", but that will entirely depend on your facility, products you produce and of course your hazard analysis and risk assessment.
Clear as mud, I know. If your hazard analysis and risk assessment clearly identify which of your Preventive Controls are Process Preventive Controls, and you treat them the same as CCP's, you should be good.
Just a word of caution to those that think you can use a COA from a supplier as a Supplier Preventive Control for raw materials that contain hazards.... don't.
The FDA inspector we had earlier in the year for a 3.5 day FSMA Readiness Evaluation specifically stated that FDA will not accept that.
Hope that helps,