The identification of allergen control as a CCP within a food processing operation, a process of validation and testing must be established to ensure that these controls are sufficient and appropriate as well as effective.
The review and repeating of validation steps should be driven by the company's allergen risk assessment process as well as following any changes to production methods, raw material supply, method of cleaning or chemical regime.
It is in the area of testing that science has yet to catch up with the legislative and consumer requirements. There still remains some items on the Food Labelling (No 2) (Amendment) Regulations 2004 which cannot be tested unless within a specialist laboratory. There are, however, approved factory-based testing protocols which can be effectively employed.
All testing falls into one of two categories: - validation testing or verification testing.
A quantitative process, validation testing for allergens normally employs Enzyme-Linked Immunosorbent Assay (ELISA) technology or DNA identification, although the latter is only semi-quantitative.
The limits of detection for ELISA methods will vary between allergenic proteins, however they are typically in the μg region (parts per million) between 0.5 and 20 ppm.
The major downside for the food processing industry, of ELISA systems is the cost (typically £75 per sample) and the time factor which is measured in days – and for this reason this technology can only be used to validate that an allergen has been removed.
Specific tests exist which can deliver a presence/absence result in a matter of minutes, ensuring that a surface can be made available for processing in the knowledge that the allergen of concern is not present.
The technology is similar to ELISA in that an antibody – antigen reaction is taking place with a visual indication revealing the presence or absence of the allergenic protein.
Using this technology either a food sample or environmental contact swab can be taken to test for the presence of, for instance: Peanut, Hazelnut, Almond, Casein (Milk), Egg, Gluten, Shellfish & Soya.
For non-specific allergen testing several systems exist all based around the detection of ATP or protein residue, with the theory that any residue should be absent following an effective cleaning regime.
The most sensitive of these systems has been developed by Tecra and can detect down to the 10ppm level for a range of allergens including egg, soy flour, peanut, gluten and almond; however the swab requires incubation at 55ºC for 15 minutes in order to produce a result.
This system will only determine that a protein is present and cannot distinguish between the allergenic compounds. As an alternative to specific allergenic protein detection, research is underway to establish if ATP based detection systems, already in widespread use throughout the food industry, can be utilised.
The challenge with employing this technology is that the system detects Adenosine Triphosphate (ATP) which could remain on food contact surfaces following cleaning activities from a number of sources. Although the assertion that if no ATP is present then a surface must have undergone a thorough clean and therefore any allergens that were present must have been removed is, on face value, understandable, the requirements of a Due Diligence defence is that the company took “all reasonable precautions” and a failure to employ a specific detection and verification system / technique where one exists may fail to meet these requirements.
The use of microbiological assessment methods have also been proposed, but the assumption that a microbiologically effective clean will ensure complete removal of allergens is flawed. This is because a rinse and application of a disinfectant may pass microbiological analysis without achieving the removal of all allergenic compounds present following a food manufacturing process.