What this is
What is a metal detection check?
What is a metal detection check?
A metal detection check is a routine test in which certified ferrous, non-ferrous and stainless steel test pieces are passed through a working metal detector to confirm it still detects and rejects at its validated sensitivity. It is run at start up, at defined intervals during production, and at the end of a run.
What is the difference between validation and verification for a metal detector?
Validation proves the detector is capable of controlling the hazard, established once under worst-case conditions of product, orientation and line speed. Verification proves it is still doing so, and is the routine check recorded on this template. Auditors treat them as separate obligations and ask to see both.
Scope
When is a metal detection check required?
Metal detection is only a CCP where your hazard analysis says it is. Running checks on a detector that your HACCP plan does not treat as a critical control creates records you must then defend, while a genuine CCP with a gap in its check record puts every run since the last good check in question.
Use this template when
- Metal detection is identified as a CCP or preventive control in your HACCP plan and needs routine verification evidence
- A production run is starting, ending, or crossing a defined interval within the run
- A product changeover has occurred and phase angle and sensitivity need reverification for the new product
- The detector has been serviced, moved, or has had a parameter changed since the last check
- A reject was recorded and you need to confirm the detector and reject mechanism are still performing before restarting
Do not use it for
- Annual or semi-annual verification by the manufacturer or a third party, which is a separate exercise with its own record
- Initial validation of the detector against a new product, which establishes the sensitivity this check then verifies
- X-ray inspection systems, which share the logic but have different test piece conventions and image-based failure modes
- Foreign body controls that are not metal, such as glass or hard plastic policies, which sit under a different clause
- Calibration of the test pieces themselves, which is certified by the supplier and tracked as a document, not a check
Compliance mapping
Which SQF 11.2 requirements does this satisfy?
This template records the routine verification required by GFSI benchmarked schemes. It does not establish the sensitivity it verifies, and it does not on its own constitute a foreign body prevention programme.
| Clause | Requirement | Where it lands |
|---|---|---|
| BRCGS 4.10.3.1 | In-line detectors incorporate an automatic rejection device, or an equivalent controlled fail-safe where automatic rejection is not practicable | Reject system |
| BRCGS 4.10.3 | Routine verification of detection and rejection using certified test pieces, with documented results and corrective action | Test pieces |
| SQF 11.2 | Documented foreign body prevention programme with defined critical limits and corrective action procedures | Header |
| SQF 11.7 | Monitoring records signed by a responsible person | Failure response |
| HACCP principle 4 | Establish monitoring procedures for each critical control point | Test pieces |
| HACCP principle 5 | Establish corrective action when monitoring shows a deviation | Failure response |
| ISO 22000 cl.8.5.4 | Hazard control plan with monitoring and correction defined | Header |
What it does not cover
- Initial validation against a new product or packaging format, which establishes the detection limits this check verifies and is usually done with the manufacturer.
- Periodic third-party verification, which most sites run every six to twelve months and which examines the detector itself rather than its daily performance.
- The foreign body prevention programme as a whole, which also covers glass and hard plastic policy, screening, and supplier controls.
- Hold and release of affected product, which needs its own record with disposition and authorisation.
Global
Metal Detection Check requirements by country
Foreign body detection is governed by private certification schemes rather than statute, which makes the applicable requirement a function of who audits you rather than where you operate.
BRCGS Issue 9 cl.4.10; SQF; FSSC 22000
Certification requirement. Routine verification with certified test pieces, documented results and corrective action.
The audit standard your customers require determines the detail. BRCGS is the most prescriptive on detection equipment.
FSMA Preventive Controls; 21 CFR 117
Hazard analysis driven. Where metal is a hazard requiring a preventive control, monitoring, corrective action and verification are mandatory.
Metal detection is a process preventive control with its own monitoring and records requirements.
Regulation (EC) 852/2004; HACCP principles
HACCP based. Foreign body control is required where hazard analysis identifies it.
National enforcement, with retailer codes usually setting a higher bar than the regulation.
ISO 22000 cl.8.5.4
Hazard control plan with monitoring and correction defined for each control measure.
Certification auditors look for the link from validation through verification to corrective action.
How to complete it
How to complete a metal detection check, step by step
The check takes ninety seconds and the form is mostly ticks. What makes the record defensible is the handful of entries that prove the test meant something: the bracket it protects, the way the pieces travelled, and what happened in the minutes after a fail.
Last Passing Check At and Units Since Last Check are not administrative fields, they are the scope of the recall you are about to underwrite. Fill them in before the test pieces come out, because if this check fails they define exactly what goes on hold, and a bracket reconstructed afterwards from memory and line-speed arithmetic is the version an auditor will not accept.
Every test field offers N/A, and the temptation is to use it for whatever was awkward today. N/A on Stainless Result is defensible only where your validation says stainless is not a relevant contaminant for this product; N/A on Test At Worst Case Position is almost never defensible, because every aperture has a least sensitive region. Partial is not a pass either, it is a fail with better manners, and it should trigger the same look-back.
The detector registering the piece is one third of the test. The reject must actuate, the piece must land in the locked bin, and All Test Pieces Recovered must be a genuine count, because a test piece that passed through unrejected and unrecovered is a certified metal contaminant travelling towards a customer with your check record as its alibi. Record the three as separate facts, since they fail separately.
The form's order is the right order: Product Affected, Quantity Affected, Hold ID and Product Location come before Engineering Called, because the product decision is time-critical and the repair is not. Revalidated Before Restart means a passing check with test pieces, not a technician's assurance, and the two signatures do different work, the operator's says the test happened, quality's says production may continue.
What auditors find
Most common metal detection check findings
Metal detection findings cluster in a small number of places, and almost all of them are about the gap between what the detector can do and what the record proves it did.
| Finding | Clause | What fixes it |
|---|---|---|
| Sensitivity or reject threshold does not match the validated setting for the product being run. Unauthorised parameter changes between shifts are a recurring finding. | BRCGS 4.10.3 | Record the running parameters on every check and compare them against the validated settings for that product code. |
| Phase angle not reset or reverified after changeover, so product effect masks the contaminant signal. | BRCGS 4.10.3 | Trigger a check on every changeover, with phase verification as a required field rather than an optional note. |
| Check performed but no record of where in the aperture the test piece passed. | HACCP principle 4 | Record aperture position and confirm the pass was through the least sensitive region at line speed. |
| Failed check recorded with no corresponding quarantine of product back to the last good check. | HACCP principle 5 | Auto-open a hold record on any fail, scoped to the window since the previous passing check. |
| Reject mechanism not tested, only detection. The detector saw the piece but nothing proves it was removed. | BRCGS 4.10.3.1 | Confirm the reject actuated and the piece reached the locked reject bin, as separate fields. |
| Test pieces uncertified, damaged, or with no traceable certificate on file. | BRCGS 4.10.3 | Hold certificates as controlled documents and reference the test piece ID on each check. |
| Checks signed by someone not authorised as a responsible person under the programme. | SQF 11.7 | Restrict sign-off to a trained and named role, enforced by the form rather than by convention. |
| End of run check missing, so the last portion of the run has no verification bracket. | HACCP principle 4 | Make the end of run check a required step in the run closure workflow. |
| Fault or error codes present in the control panel log and not cleared before production. | BRCGS 4.10.3 | Add a control panel status check to the start-up record, with faults blocking start. |
| Check frequency defined in the plan but not actually achievable given line speed and hold capacity. | HACCP principle 5 | Set frequency from the volume you can absorb on a hold, then hold the line to that interval. |
Case in point
What a failed check actually costs
The economics of this template are unusual, because the cost of the control is set almost entirely by the interval between checks. If a detector fails its check, every unit produced since the last passing check is suspect. Nothing about the failure tells you when the detector stopped working, so the whole bracket goes on hold.
That makes check frequency a commercial decision dressed as a food safety one. A line producing 2,000 units an hour checked hourly puts 2,000 units at risk on a failure. The same line checked every four hours puts 8,000 at risk. Most sites discover this the first time they have to quarantine a shift's output over one failed stainless piece.
Why the frequency in your plan is often not the frequency you can afford
Plans commonly inherit a frequency from a template or a previous site without anyone reconciling it against throughput or hold capacity. The result is a documented interval nobody keeps, which is worse than a longer interval that is actually met, because the record then shows a pattern of missed checks.
The workable approach is to run the calculation the other way: decide the maximum quantity you can quarantine and rework or destroy without disrupting supply, divide by line rate, and set the interval from that. Then write the plan to match what the line can actually sustain.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
4 sections
- Reference
- QUA-020
- Archetype
- Checklist
- Record ID
- CHK-2026-000
- Scoring
- Pass or fail
- Direction
- High is good
- Singleton
- No
- Basis
- SQF 11.2, BRC 4.10
- Links
- Links Asset; feeds Hold
- Tags
- Quality, Food safety, CCP
- Sections
- 4
- Fields
- 45
- Follow up fields
- 7
- Repeating sections
- 0
- Links out
- 4
Header
18 fieldsCheck ID*
Auto sequence. Format CHK-2026-00000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Date and Time*
Raised By*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Line*
Shift*
Line Lead
Batch Number*
Numeric key joining to your ERP batch record.
Links to External system reference
Product*
Production Date*
Detector*
Asset ID*
Format AST-0000.
Links to FDN-002 Asset ID
Fail Means Look Back
A failed check means every unit since the last passing check is suspect. Quarantine first, investigate second.
Check Point*
Last Passing Check At*
Units Since Last Check
Test pieces
9 fieldsFerrous Size Millimetres*
Ferrous Result*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Non Ferrous Size Millimetres*
Non Ferrous Result*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Stainless Size Millimetres*
Stainless Result*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Test Pieces Passed Through Product*
Testing in air rather than in product overstates sensitivity.
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Test At Worst Case Position*
Leading edge, centre and trailing edge behave differently.
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
All Test Pieces Recovered*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Reject system
5 fieldsReject Mechanism Operated*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Rejected To Locked Bin*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Bin Full Detection Working*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Fail Safe On Air Or Power Loss*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Belt Stop On Reject Failure*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Failure response
13 fieldsAny Test Failed*
- No3 pts
- Yes0 pts
Product Affected By The Failure*
- No3 pts
- Yes0 pts
Quantity Affected
Hold ID
Raise the hold record, then enter its reference.
Links to QUA-003 Hold ID
Product Location
Where the affected product physically is right now.
Engineering Called
Work Order ID
Links to MNT-002 Work Order ID
Case ID
Thread key
Revalidated Before Restart
- Yes3 pts
- No0 pts
Operator*
Signature*
Quality*
Second Signature*
QUA-020 · record IDs look like CHK-2026-000 · Links Asset; feeds Hold
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The check itself takes ninety seconds. What fails is everything around it: the interval that slips on a busy shift, the changeover nobody flagged, the failed check where the hold never got opened.
Schedules checks against the interval in your plan, blocks run closure until the end of run check is recorded, and opens a hold automatically on any fail, scoped back to the last passing check.
Watches the asset record. A service, a move or a parameter change on the detector triggers a reverification task before the line runs again.
Holds the responsible person roster, so sign-off is restricted to trained and named staff and expiring competencies surface before they lapse.
Rolls check completion, deviation counts and open holds into one view, and holds every write for your approval.
This template lives in KnowQuality — quality and food safety. HACCP, nonconformance, traceability, laboratory and customer complaints.
Meet KnowQuality→Glossary
Metal Detection Check definitions and key terms
- Critical control point (CCP)
- A step where control is essential to prevent or reduce a food safety hazard to an acceptable level. Metal detection is a CCP only where the hazard analysis says so.
- Validation
- Evidence obtained once that the control is capable of achieving the required result under worst-case conditions of product, orientation and line speed.
- Verification
- Routine evidence that the validated control is still performing. This template is a verification record.
- Test piece
- A certified sphere of ferrous, non-ferrous or stainless steel at the validated detection limit, usually carried in a card or stick with a traceable certificate.
- Product effect
- The electromagnetic signal generated by the product itself. Moisture, salt and conductive ingredients produce strong signals that can mask a contaminant.
- Phase angle
- The setting that separates the product signal from a metal signal. Set per product and reverified after every changeover.
- Least sensitive region
- The part of the aperture where detection is weakest, usually the geometric centre. Test pieces must pass through it for the check to be meaningful.
- Hold and release
- Quarantine of all product back to the last passing check following a failure, with a documented disposition decision before any release.
FAQ
Frequently asked questions about metal detection check
How often should a metal detector be checked?+
At start up, at defined intervals during the run, at the end of the run, and after any changeover or parameter change. The interval itself should be derived from how much product you can afford to quarantine, since a failure puts everything back to the last passing check on hold. Hourly is common on high-value lines; two to four hours is common elsewhere.
What size test pieces should we use?+
The sizes established by your validation for that product, not a generic figure. Published guidance for dry products commonly cites the region of 1.5mm ferrous, 2.0mm non-ferrous and 2.5mm stainless as achievable minimums, but wet, salted and conductive products need product-specific validation because of product effect, and the achievable limit is often larger.
What happens if a metal detection check fails?+
Quarantine all product back to the last passing check, since nothing indicates when detection stopped working. Investigate the cause, confirm the detector and reject mechanism after any correction, run a passing check before restarting, and record the disposition of the held product before any release.
Does the reject mechanism need testing separately from detection?+
Yes. Detection and rejection are separate functions and a detector can register a contaminant without the reject actuating. BRCGS clause 4.10.3.1 addresses the rejection device specifically. Record both that the detector signalled and that the piece was physically removed to a secured reject location.
Is metal detection always a CCP?+
No. It is a CCP only where your hazard analysis identifies metal contamination as a significant hazard controlled at that step. Where it is a prerequisite or a customer requirement rather than a CCP, the checks still matter but the critical limits, monitoring and corrective action obligations attach differently.
Who is allowed to sign off a metal detection check?+
A responsible person as defined in your programme, which normally means someone trained on the detector and named in the plan. SQF requires monitoring records to be signed by a responsible person, and checks signed by unauthorised staff are a recurring finding even where the check itself was done correctly.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Used together in Foreign Body Control
X-Ray Inspection Verification
Verifies x-ray detection using the specified test pieces, in product, at the worst case position
Sieve and Filter Integrity Check
Checks sieves, filters and magnets for damage, correct aperture and secure fitting, and records what was retained
Blade and Sharps Accountability Record
Accounts for every blade, needle, cutter and sharp issued into a production area and returned at shift end
Wood and Pallet Control Check
Checks that wood, wooden pallets and similar materials are excluded or controlled in production areas
Foreign Body Trend Review
Reviews foreign body findings and complaints over a period to identify the source rather than treating each one alone
Foreign Body Awareness Training
Covers the sources of foreign body on this site, what to do when one is found and why the search matters more than the finding
More in Quality Inspections
Incoming Material Inspection
Checks material against specification before it is accepted into stock
First Article Inspection
Checks the first piece from a new setup or changeover against every specified characteristic
In Process Inspection
Checks product at set points during production, against the control plan
Final Product Inspection
Checks finished product before it is released to the customer
Packaging Inspection
Checks packaging integrity, labelling, coding and seal quality
Label Verification Check
Confirms the label on the line matches the product being run, including allergens, weight and date code
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- BRCGS Global Standard for Food Safety, Issue 9, clause 4.10 (foreign body detection)
- SQF Food Safety Code, foreign body prevention and monitoring record requirements
- Codex Alimentarius HACCP principles 4 and 5, monitoring and corrective action
- ISO 22000:2018 clause 8.5.4, hazard control plan
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.