HomeSimulated use of thresholds for PAL: Impact of prevalence and risk

Simulated use of thresholds for PAL: Impact of prevalence and risk

Dr. Silvia Dominguez

Written by: Dr. Silvia Dominguez, Research Associate, Université Laval

Context:

PAL is used by food manufacturers based on different criteria and is not subject to specific regulation. This has led to allergic consumers’ confusion, as they cannot consistently interpret the risk associated with this type of labelling. The FAO/WHO Expert Consultation on Risk Assessment of Food Allergens (2023) recommended the use of allergen concentration thresholds to standardize the use of PAL among food manufacturers. These thresholds are calculated considering allergen reference doses that would not trigger a reaction in most allergic consumers.

What we studied and why:

The purpose of our study was to explore what the adoption of thresholds for PAL would mean in terms of predicted number of allergic reactions. To do so, we designed simulations for specific food categories and allergens, comparing 2 scenarios:

  • Allergic reactions caused by products with PAL. This reflects the current situation, where PAL is not specifically regulated, it is applied by manufacturers based on different criteria, and allergic individuals consume products with PAL due to confusion or assuming it not to be valid; and,
  • Allergic reactions caused by products without PAL. This reflects a hypothetical scenario where PAL is applied based on recommended thresholds, and allergic consumers systematically avoid products with PAL, recognizing it as a valid statement based on a manufacturer’s risk assessment.

What our simulations showed:

  • Under scenario 1, among the food categories and cross-contact allergens studied:
    • Several seem to be unnecessarily using PAL.
    • Milk posed the highest risk and peanut, the lowest.
  • In most cases studied:
    • The estimated number of reactions attributed to scenario 1 would be higher than that attributed to scenario 2.
    • If thresholds for PAL based on allergen doses estimated not to trigger a reaction in 95% (ED05) or 99% (ED01) of the allergic population are applied, products without PAL (scenario 2) would result in very few and generally mild adverse reactions.

Why our findings are important:

This was the first study to quantitatively assess the impact of a potential adoption of thresholds for PAL. Our results provide objective data supporting expert recommendations of this approach. Using PAL based on thresholds could increase the number of safe options for individuals with food allergy and facilitate interpretation of PAL in terms of risk. However, for this strategy to succeed, allergic consumers’ avoidance of products with PAL is crucial, and would require significant education efforts.