What is HACCP, in plain terms?

HACCP — Hazard Analysis and Critical Control Points — is a documented food-safety management system. You map where in your process food could become unsafe, identify the few points where control is critical, set limits at each of them, and monitor and record that you are staying inside those limits. It is a way of operating, written down and evidenced, not a one-off certificate you hang on the wall.

From HACCP Certification in Dubai: Requirements, Timeline and the Process — the full reading, with the method behind this answer.