Validation of the cleaning allergens

To ensure proper validation, we've created a step-by-step plan (see the download above). The key points are summarized below.

Before a validation is started

Before a validation plan can be developed, the basics must be in place. It's important to have a cleaning plan or matrix available for each process or component. For various cleaning procedures, it must be clear which cleaning method will be used after a specific allergen transition. This requires an overview of all allergenic raw materials used in each process.
Validation is performed under normal conditions, not when cleaning is forgotten or when extra thorough cleaning is carried out.
Check if there are any specific requirements for the validation plan, such as the number of cleanings to be validated or the methods used. These can be found in guideline documents or customer-specific requirements (Code of Practice).

Which machines and lines?

It's important to determine which machines and objects require validation. This applies to all process steps, storage, and transport systems (such as silos, tanks, standard carts, reused big bags, etc.). The greatest risk of cross-contamination arises from direct product contact via shared production lines and equipment. Therefore, create an overview of all process steps where cross-contamination can occur, including supporting processes such as pouring, weighing, mixing, size reduction, and packaging. Also identify shared line objects, accessories, and cleaning equipment.
Airborne transmission poses only a limited risk of food allergen contamination. The presence or odor of allergens in a space does not pose a risk. Only in extreme cases, when food is transported by dust or air movement (compressed air), can airborne contamination become a factor.
We have a separate validation protocol available for this.

Determining the cleaning for validation

All cleaning methods used during an allergen transition must be assessed and validated. Consider:

• Intermediate cleaning/water rinsing
• End of day cleaning
• Deep cleaning (weekend)
• CIP programs and other object cleaning

If different cleaning methods are used during the same worst-case product transition, the least effective cleaning method is validated. This demonstrates that the cleaning method is effective even in the worst-case scenario.

Worst-case approach

Cleaning validation is performed based on the most unfavorable product transition: from a product with the highest allergenic protein content to one that is absent. The product with the highest allergenic protein content is considered, taking both the percentage of the raw material and the protein content into account. This quantity must be high enough (preferably > 1000 mg/kg protein from the allergen source). At lower concentrations, the chance of detection is low, even after less thorough cleaning.

Also consider the cleanability of the product matrix when choosing the product transition method. Ideally, choose a cleaning method after sticky products or products with bits. If the cleaning has been proven effective under the most adverse conditions, it will also be effective in less severe scenarios.
If allergens are evenly distributed in a product, validation is not necessary for all allergens.

Choice of analysis method

Laboratories
ServiceFor validation, it is important to choose the correct analytical method. Laboratory analyses (quantitative determination) are preferred.
Tip: Part of our laboratory service is advice on the correct analysis method.
When choosing the method, pay attention to:

• Availability of a suitable method per allergen (e.g. PCR for celery if ELISA is not available).
• The presence of specific proteins. Some milk ingredients, such as whey, do not contain casein but rather another milk protein: ß-lactoglobulin.
• Effects of processing (such as heating or fermentation) on the level of an allergen. For example, in highly heated products containing egg or soy, very little of the allergen is measured, even though it can still cause allergic reactions.
• The detection limit must be (preferably 3x) lower than the standard or safe limit used.
• Potential cross-reactions with similar proteins. Similar protein structures in other products may be detected and incorrectly interpreted as the allergen to be measured.

Determine the samples to be taken

The sampling plan describes which samples should be taken and where or when. 

• Product samples:
  • Positive control (cleaning product)
  • Starter product after cleaning. Note any downgrade quantity of product or product needed to regulate machinery. Always take a sample of the first product intended for sale.
  • Samples over time, as cross-contamination can occur not only at the start of a production.
• Swabs: Take samples from surfaces using the cross-sectional technique. This allows us to determine whether allergens are present on cleaned surfaces. Swabs are qualitative (presence/absence) rather than quantitative, as they measure per cm² and not in mg/kg or ppm like product analyses. Therefore, they cannot be used for risk assessment, but only to determine where cleaning may be incomplete.
  Do not use swabs for microbiological examination because these fluids may contain allergens (peptone). Er are special swab sets for ELISA or PCR analyses.
• Rinsing water: This may be necessary for closed systems. It is not preferred due to the high degree of dilution.
• Air: usually not needed, see above.

Prevent cross-contamination when taking samples. Also check for contamination of materials and sample taps. For product analysis, collect sufficient material (200 grams) and a representative sample.

Establishing approval and rejection limits

After thorough cleaning, allergens should hopefully no longer be detectable. In some cases, such as with dry cleaning, product residues and therefore allergens may remain. Therefore, set limits for the various samples. Product analyses can reference doses and the action limits derived from them are used. Results from swabs and rinse water provide insight into cleaning effectiveness, but cannot be compared with these limits. Experience shows that swabs can be positive while no allergen is found in the product analysis. This is due to a lower detection limit for swabs, but also because any contamination on a surface is not fully transferred to a product that comes into contact with the contaminated surface. Rinse water analysis rarely finds contamination due to the dilution effect. Product residue measurements (turbidity measurements) are often more accurate than ELISA or PCR analyses.

Performing cleaning and sampling

Perform the cleaning according to the established plan. Visually inspect the line and immediate surroundings before taking samples. Check for any remaining product residue and take photos if necessary. Send the samples to an experienced laboratory that uses the selected analysis method.

Interpretation of the results

Before reported values ​​can be compared with established limits, it must first be determined whether they have the same units. Standards are often expressed in mg of total allergen. protein/ kg product.
Results of allergen analysis can be expressed as allergen product, suballergenic (ß-lactoglobulin, gliadin, tropomyosin) or DNA copy number.
A conversion factor, such as a protein conversion factor, is often required. We always provide conversion factors, but please request them if necessary if using a different laboratory. If all product analyses are positive after cleaning, check for any potential cross-reactions (false positives) or whether raw materials may have been contaminated from the supply chain.
Ensure that all results are compiled into a readable report with clear conclusions.

If positive results are obtained after cleaning, adjustments to the procedure may be necessary, such as adjusting the cleaning time or program, intensifying the cleaning, or using a different cleaning agent. Then, repeat the cleaning validation after adjustments. 

Verification

A validation is a comprehensive study typically performed for new equipment or changes to the process, product, or cleaning process. This is often repeated at least every 3-5 years.

Products
rapid testsTo regularly check cleaning procedures, a verification can be performed. This can be useful for free-of-product claims or high-risk situations. Allergen rapid tests, general protein tests, UV inspections, or sometimes ATP measurements (heated products don't always have sufficient ATP) can be used for this purpose. See also our range of rapid tests for verification.

Need help?

We can assist with developing a comprehensive validation plan. We will work with you to determine which samples need to be taken and which methods are most suitable. In many cases, it's recommended that the organization take the samples themselves; we will then arrange for the necessary materials to be sent. After receiving and analyzing the samples, we will prepare a complete validation report. This report is suitable for use in customer audits—particularly for private label production—, certification audits, and regulatory oversight. In addition, the results can serve as input for a risk assessment (such as a QRA or VITAL), which can be used to determine whether an allergen warning (Precautionary Allergen Labelling, PAL) is required on the label.

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