How are critical limits established for critical control points in a HACCP plan?

Critical limits for critical control points (CCPs) in a HACCP plan are established based on scientific data and regulatory requirements to ensure that the CCP effectively controls the identified hazard. A critical limit is the maximum or minimum value to which a physical, chemical, or biological parameter must be controlled at a CCP to prevent, eliminate, or reduce to an acceptable level the occurrence of a identified food safety hazard. Critical limits are not the same as operational limits, which are set more stringently for proactive control. They are set at the extreme boundaries of safety. The establishment of critical limits involves considering factors such as the nature of the hazard, the characteristics of the food product, the processing conditions, and the capabilities of the monitoring equipment. Sources of information for establishing critical limits include scientific literature, regulatory guidelines, expert opinions, and in-plant studies. For example, if a CCP is cooking poultry to kill Salmonella, the critical limit might be an internal temperature of 74°C (165°F) for at least 15 seconds, based on scientific studies demonstrating that this temperature and time combination effectively eliminates Salmonella. If a CCP is metal detection, the critical limit might be the maximum size of metal fragment that the detector can reliably detect. Critical limits must be measurable and verifiable to ensure that they can be effectively monitored. When establishing critical limits, it is important to consider the variability of the process and to build in a safety margin to account for potential fluctuations. If a critical limit is exceeded, it indicates that the CCP is out of control, and corrective actions must be taken to bring the process back into control.