Documented and validated cleaning procedures are critical to avoid allergen cross contamination. You need to seek out and inspect all the trouble spots. Cleaning practices that are satisfactory for hygiene purposes may not be adequate to remove all allergens. Equipment may for example need to be dismantled to remove allergen residues. A tool you can use to validate your cleaning is to test for allergen residues.
Many test methods are commercially available for food allergen analysis. Most of the analyses are immunochemical methods such as ELISA but DNA-based detection based on PCR is growing in popularity. However, the development of analytical methods to detect levels of allergens is still at an early stage. EU has not yet agreed independently validated methods for all the allergens for which ingredient labelling is required. The kits that are currently available may vary in how sensitive and specific they are. They may also vary in how effective they are to analyse different food materials.
At the moment you can therefore choose to validate your cleaning procedure by looking thoroughly at the production line after cleaning.
If it is not possible to clean your production line adequately you need to assess the risk of allergen cross contamination and if appropriate use advisory labelling.
- Jackson LS, Al-Taher FM, Moorman M, DeVries JW, Tippett R, Swanson KMJ, Fu T-J, Salter R, Dunaif G, Estes S, Albillos S, Gendel SM (2008). Cleaning and other control and validation strategies to prevent allergen cross-contact in food-processing operations. J Food Prot 71, 445-458.
More detailed information on food allergen analysis: S Kerbach, AJ Alldrick, RWR Crevel, L Dömötör, A DunnGalvin, ENC Mills, S Pfaff, RE Poms, B Popping, S Tömösközi (2009). Managing food allergens in the food supply chain – viewed from different stakeholder perspectives. Quality Assurance and Safety of Crops & Foods, 1(1), 50-60.
Allergen analysis news from the MoniQA consortium (Monitoring and Quality Assurance in the Food Supply Chain).