With 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 as there remain some items on The Food Labelling (No 2) (Amendment) Regulations 2004 which cannot be tested for outside of a specialist laboratory. There are, however, factory-based testing protocols which can be employed.
All testing, however, falls into one of two categories: - Validation testing or Control testing.
Validation testing for allergens is a quantitative process normally employing Enzyme-Linked Immunosorbent Assay (ELISA) technology or DNA identification, although this 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.
However 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 – for this reason this technology can only be used to validate that an allergen has been removed.
Control methods, once again, fall into two categories; allergen specific and non-specific.
Specific Allergen Testing
Currently only one allergen specific test exists which can deliver a presence / absence result in a matter of minutes thereby allowing a surface to be released. This 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.
This technology allows for either a food sample or an environmental contact swab to be tested for the presence of for instance: Peanut, Hazelnut, Almond, Casein (Milk), Egg, Gluten, Shellfish & Soya
Non Specific Allergen Testing
For non-specific allergen testing, however, several systems exist all based around the detection of protein residue – the theory here is that any protein 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. As discussed previously, 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 difficulty with employing this technology is that the system detects Adenosine Triphosphate which could remain on food contact surfaces following cleaning activities from a number of sources and not the specific proteins involved in allergen control.
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”. Arguably, a failure to employ a specific detection and verification system / technique where one exists would fail to meet these requirements.
The use of microbiological assessment methods have also been proposed, once again 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 a removal of any allergenic compounds present following a food manufacturing process.