GIFSQ Tools · Module 13 — HACCP, Food Safety & Regulatory Compliance · Tool 253 of 500
Read an environmental monitoring period at a glance: positive rate, alert-limit rate and action-limit rate, with the control status for the period.
Try sample values — fills the form with the worked example below.
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Positive rate (%)
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Alert-limit rate (%)
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Action-limit rate (%)
Equation: Positive rate (%) = positives ÷ total samples × 100. Alert-limit rate (%) = samples over the alert limit ÷ total samples × 100. Action-limit rate (%) = samples over the action limit ÷ total samples × 100. Status: Action required when any sample is over the action limit; Investigate when the alert rate is over 10% with no action-limit breach; otherwise In control.
Method: Environmental monitoring trending per ISO 22000:2018 verification of prerequisite programmes and the trending approach in the FDA guidance on environmental monitoring for ready-to-eat foods. Alert and action limits are set by the site from its own baseline data — there is no universal limit.
Assumptions: all counts are for the same period and the same programme; a sample over the action limit is also a positive, but the counts are entered separately.
Limitations: rates describe the period — a low rate does not prove the environment is clean, and a single action-limit result needs investigation whatever the rate is.
Rounding: rates to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: Environmental monitoring trending per ISO 22000:2018 verification of prerequisite programmes and the trending approach in the FDA guidance on environmental monitoring for ready-to-eat foods. Alert and action limits are set by the site from its own baseline data — there is no universal limit.
Assumptions: all counts are for the same period and the same programme; a sample over the action limit is also a positive, but the counts are entered separately.
Limitations: rates describe the period — a low rate does not prove the environment is clean, and a single action-limit result needs investigation whatever the rate is.
Rounding: rates to 2 decimal places; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: 120 samples, 6 positive, 4 over the alert limit, 1 over the action limit: positive rate 5.00%, alert rate 3.33%, action rate 0.83% — Action required.
Enter values above to see results.
Any action-limit result needs a documented investigation and corrective action, even when the overall rate looks low. Tool 253 of 500 — GIFSQ
