I just started to learn about HARPC. The main difference, as I understand, is that the risk assessment in HACCP is made in the presence of preventive controls and HARPC in the absence of it. In HACCP you control risk and in HARPC you prevent it. HARPC, for me, is more strict or requires more work before implementation to identify more risks, HACCP requires more work after implementation related to nonconformities and corrective actions. I am still learning both models, I used to work with HACCP, now, I will start with HARPC. I hope read more about this topic in the blog.