In a HACCP plan, what is a 'critical limit'?

CRITICAL LIMIT (HACCP Principle 3): A maximum and/or minimum value to which a biological, chemical, or physical hazard must be controlled at a critical control point (CCP) to prevent, eliminate, or reduce it to an acceptable level. EXAMPLES: Cooking chicken to a minimum internal temperature of 165°F (the critical limit is 165°F); cooling cooked food from 135°F to 70°F within 2 hours (the critical limit is the time/temperature combination); holding hot food at a minimum of 135°F; CRITICAL LIMITS must be: measurable (temperature, time, pH, water activity); science-based; clearly defined; MONITORING (Principle 4) checks whether critical limits are being met; if a critical limit is NOT met, a CORRECTIVE ACTION (Principle 5) is required; critical limits are the measurable boundaries that separate safe from unsafe at each critical control point; setting appropriate, science-based critical limits is essential to an effective HACCP plan.