Principle 3: Establish the Critical Limits

Statement

A critical limit is the maximum or minimum value for the control measure at a CCP to prevent, eliminate, or reduce the hazard to an acceptable level.  It separates acceptable (safe) product from unacceptable (unsafe) product.

How is this stage achieved?

Once the CCPs in the product/process/module under study have been identified, critical limits should be specified for the control measure(s) at each CCP.

The critical limit is the value which separates acceptable (safe) product from unacceptable (unsafe) product and the level needs to be clearly defined.

Critical limits should be for the control measure and not the hazard.  They should be:

• Measureable

• Observable

• Able to monitor in “real time” (quickly)

Some critical limits are defined in:

• Legislation

• Industry guidelines and codes of practice

Others can be determined from:

• Collection of experimental data during trials

• Advice from specialists with expert knowledge

Criteria often used to set a critical limit include measurements of:

• Temperature

• Time

• Moisture level

• pH (level of acidity)

• Aw (level of water available to support the growth of a hazard such as bacteria)

• Chemical analyses

• Available chlorine

• Subjective data e.g. visual observations/assessments.  For sensory parameters such as visual appearance and texture clear guidance on the requirements for compliance is necessary with practices, procedures or pictorial examples (e.g. photographs) of what is acceptable.

In addition to a critical limit some businesses may set target levels.

Critical Limit    A criterion which separates acceptability (safe) from unacceptability (potentially unsafe).

Target Level    A predetermined value for the control measure which has been shown to eliminate a hazard at a CCP.

Tolerance        The values between the target level and the critical limit.

Deviation         Failure to meet a critical limit.

Example

Documentation and Records

Details of how the critical limit was established (including sources of information or data used) need to be recorded.

Review

A review of this principle should be scheduled and triggered if there are changes within the company or new information becomes available (e.g. legislation, emergence of a new hazard) see Principle 6.