Water reuse is becoming increasingly common in food processing as manufacturers seek to reduce water consumption. Despite increasing water reuse, there has been no direct research into the occurrence of allergens in food-processing water or whether current water-treatment systems adequately remove them. Treatment and monitoring practices are also not standardised.
A new review examines the food allergen cross-contact potential across water-intensive operations including product washing, immersion tanks, peeling and shelling, meat and poultry processing, clean-in-place systems and produce flumes. It proposes that processes involving extensive food-water contact or disruption of food tissues could allow allergenic proteins to enter and accumulate in water, potentially exposing products processed subsequently.
Characteristics that make some allergens relatively stable in foods, including molecular structure, size, resistance to degradation and interactions with fats and other proteins, could also allow them to persist during water treatment. Common treatment technologies may perform differently depending on these characteristics.
The review identifies a possible blind spot in allergen management and calls for research to determine whether allergenic proteins survive water conditioning, transfer to subsequently processed foods, and remain immunoreactive. Approved detection methods and validated monitoring approaches will be needed as water reuse becomes a bigger part of sustainable food production.
Reference: Maal-Bared et al. Allergen persistence and cross-contamination potential in water reuse within food industry processes. npj Clean Water, 9, 66 (2026). DOI: 10.1038/s41545-026-00634-y. Available with Open Access here.
