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Guide

Allergen Cleaning Validation: Protocol, Report and Worked Example

When a line runs allergen and allergen free products, the clean between them is often the control everything else depends on. Your allergen risk assessment assumes that clean works. Validation is how you prove it, and verification is how you show it keeps working. This guide explains the difference, how to write a protocol, which test methods suit which job and how to structure your report.

This resource is provided as a guide only and does not constitute legal or professional advice. Always confirm requirements with your certification body, customers and regulators. Use of this content is at your own risk.

What Is Allergen Cleaning Validation?

Allergen cleaning validation is gathering documented evidence that a specific cleaning procedure reliably removes a specific allergen from equipment to an acceptable level, before you rely on it as a control. Routine verification then checks, at each changeover, that the validated clean is being carried out and continues to work.

In the US, 21 CFR 117.35(a) says cleaning "must be conducted in a manner that protects against allergen cross-contact", and food allergen controls are a named preventive control under 117.135(c)(2).

Validation vs Verification

Validation vs Verification
ValidationVerification
QuestionDoes this cleaning procedure work?Was it done properly this time?
WhenBefore relying on the clean, and after significant changesAt every changeover or on a set schedule
Typical evidenceAllergen specific testing over repeated trialsVisual inspection, rapid checks and records

There is no legal test method for either. The approach below reflects common industry practice.

Writing the Validation Protocol

A protocol should set out, before testing starts:

  1. Scope: the line, equipment, product and allergen being validated.
  2. Worst case: the hardest to clean product, highest allergen level and longest run.
  3. Cleaning procedure: the exact method, chemicals, times and people, as written in your SOP.
  4. Sampling plan: swab sites, including hard to clean points, plus rinse water or first product off the line where relevant.
  5. Test methods: which methods you will use, and why.
  6. Acceptance criteria: what result counts as a pass. No UK or US legal level exists, so sites define and justify their own.
  7. Number of trials: how many repeat cleans you will test, enough to show the result is consistent.

Test Methods: Visual, ATP, Protein Swabs, Allergen Specific Kits

Test Methods: Visual, ATP, Protein Swabs, Allergen Specific Kits
MethodWhat It ShowsUse For Validation?
Visual inspectionNo visible residueSupporting evidence only
ATPGeneral organic residueNo: ATP is not allergen specific
General protein swabsProtein residue, not allergen specificSupporting evidence
Allergen specific kits (ELISA, lateral flow)Presence of the target allergenYes, common industry practice

ATP can be useful for routine hygiene verification, but it does not validate allergen removal.

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Worked Example and Report Structure

Illustrative example: a sauce line switching from a milk containing product to a milk free product.

  • Worst case: the highest milk recipe, run for a full shift.
  • Procedure: the documented wet clean in the SOP.
  • Sampling: swabs from the mixer paddle, pump outlet, filler nozzle and a known dead leg, plus first product off the line.
  • Testing: milk specific lateral flow on swabs and ELISA on product, repeated over several cleans.
  • Outcome: all results meet the site's acceptance criteria, so the clean is validated. Any failure means revising the procedure and retesting.

This example is illustrative and not a sourced case study.

Report structure:

  1. Scope and objective
  2. Protocol summary and worst case rationale
  3. Cleaning procedure reference
  4. Sampling sites and methods
  5. Results for each trial
  6. Conclusion and acceptance decision
  7. Routine verification plan
  8. Revalidation triggers
  9. Approval and sign off

Validated cleaning supports your allergen controls, but it does not on its own remove the need to consider precautionary labeling. That decision belongs in your allergen risk assessment. Routine checks at changeover belong in your pre-operational inspection, and wider hygiene verification in your environmental monitoring program.

Revalidation Triggers

Revalidate when something could change how well the clean works:

  • New products, recipes or allergens on the line
  • New or modified equipment
  • Changes to cleaning method, chemicals or times
  • Failed verification results or allergen complaints
  • At a periodic review set in your own procedure

FAQs

What is the difference between allergen cleaning validation and verification?

Validation proves a cleaning procedure can remove an allergen; verification checks it was done properly each time. Validation happens before you rely on the clean, while verification is routine, usually at every changeover.

Can ATP testing validate allergen cleaning?

No. ATP detects general organic residue and is not allergen specific, so it cannot prove an allergen has been removed. Use allergen specific methods such as ELISA or lateral flow for validation.

How often should allergen cleaning be revalidated?

Revalidate whenever products, equipment, cleaning methods or results change, and at a periodic review you define in your own procedure.

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