Home/Resources/Specialty Food Manufacturing/Calibration of temperature probes for FSMA records
Preventive · 7 min read

Calibration of temperature probes for FSMA records

Cooling records are only as good as the probes that produce them. Drift of 2°F at the chiller probe can fail a batch FDA inspection that the cooling itself would have passed. Calibration discipline turns the record into evidence.

Section 01

Why calibration matters

21 CFR 117 verification subpart requires calibration of monitoring equipment used for preventive controls. Cooling-step probes are the most common monitoring equipment in specialty food production. FDA reviews calibration records as the first verification check.

Without calibration records, the cooling record is unverifiable.

Section 02

Ice-point method

The most common field calibration. Crushed ice fully wetted with distilled water, equilibrated 5 minutes, reads 32.0°F (0.0°C). Probe inserted to depth, allowed to equilibrate, reading recorded. Acceptable: ±1.0°F for most field probes; ±0.5°F for critical PCHF probes.

Document temperature, technician, time, probe ID, and result every time.

Section 03

Boiling-point method

For high-range calibration. Boiling distilled water at sea level reads 212.0°F (100.0°C); adjust for elevation (Tampa is sea level so standard applies). Less common because cooling-step probes operate at the cold end; still useful for cook-step probes.

Same documentation discipline.

Section 04

Reference probe method

NIST-traceable reference probe used to verify field probes. Most specialty food plants own one calibrated reference; calibration of the reference itself is sent out annually to a certified lab.

Reference probe approach is the gold standard for FDA inspection-readiness.

Section 05

Calibration cadence

Quarterly for cooling-step probes. Monthly for high-criticality processes (pasteurization, FSIS-inspected operations). After any event that could damage the probe — drop, exposure to extreme temperature, electrical fault.

Document the cadence in the verification subpart of the Food Safety Plan.

Section 06

Out-of-tolerance procedure

When a probe reads out-of-tolerance: replace or recalibrate per manufacturer procedure. Investigate the impact on records since the last in-tolerance calibration. PCHF corrective action procedure activates if records were affected.

Document everything. The investigation record is part of the corrective action file.

Operator FAQ

Quick answers

How often should I calibrate?

Quarterly minimum for cooling-step probes. Monthly for high-criticality processes.

What's the ice-point method in 30 seconds?

Crushed ice fully wetted with distilled water, equilibrated 5 minutes, reads 32.0°F. Insert probe, wait, read, document.

Do I need NIST-traceable equipment?

FDA expects calibration to be traceable to a recognized standard. Ice-point with distilled water is acceptable; NIST-traceable reference is gold standard.

What's the tolerance?

±1.0°F for most field probes; ±0.5°F for critical PCHF probes. Specify in your Food Safety Plan.

Does ColdSentry™ probes need calibration?

Yes. ColdSentry™ probes are calibrated at deployment and periodically thereafter. Suncoast Cold Systems documents calibration as part of service contract scope.

Get help

Need a tech for this in Tampa Bay?

Suncoast Cold Systems handles process refrigeration and cooling for specialty food manufacturers across Tampa, St. Petersburg, Clearwater, Brandon, Riverview, Temple Terrace, and Wesley Chapel. 24/7 dispatch. Licensed Class A A/C Contractor (FL #CAC1824642), EPA 608 Universal, OSHA 30 Construction.

Call (813) 599-5988 Request service
More

Keep reading

Preventive10 min

Preventive maintenance for process refrigeration

Calibration as part of PM.

Read the note
Compliance10 min

FDA 21 CFR 117 PCHF process controls

Verification subpart that scopes calibration.

Read the note
Preventive9 min

CIP sanitation for cooling equipment

Sanitation companion to calibration.

Read the note