Allergen testing guidance offers hope to frustrated food manufacturers

By Elaine Watson

- Last updated on GMT

Related tags Elisa

New guidance promising to alleviate the nightmares caused by inconsistent results from allergen testing kits has been published by an industry taskforce.

The guidance, which seeks to harmonise the validation of commercially available ELISA (Enzyme-Linked Immunosorbent Assays) allergen testing kits, was drawn up by a taskforce set up by analytical standards body AOAC International.

The guidance defines a minimum standard for test kits so that food manufacturers can have greater confidence that the results they are getting will match those from customers or regulatory bodies.

While the guidance would take time to become bedded in, several ELISA kit providers had already committed to following it, revealed David Reading, an independent consultant on allergen management to the food industry and co-founder of charity the Anaphylaxis Campaign.

He added: “The lack of standardisation has caused confusion. Food manufacturers sometimes struggle to understand test results and to come to terms with apparent discrepancies, but are still basing risk management strategies on these results.

From both a practical and scientific point of view, the detection of a particular allergen is a difficult task in itself. Added to this is the variability of testing kits from different companies. Differences of perhaps five to 10-fold would not be out of the question. This can also cause problems from a regulatory point of view, with a producer testing a product as negative or below a particular level while a regulatory authority might get a positive result.”

This was a particular problem for firms supplying ‘free-from’ products, some of which had recently had products delisted after they tested positive for gluten and dairy derivatives during random sampling by customers – whereas their own tests had suggested that the products in question were free from these allergens, he said.

Dr Bert Popping, director of molecular biology and immunology at the Eurofins laboratory group, told that the guidance defined “the minimum requirement for in-house and interlaboratory study data to be obtained for a validation of kits in accordance with AOAC/IUPAC (International Union of Pure and Applied Chemistry) harmonised guidelines”.

He added: “Several institutions and organisations have contributed to this document, including several members of the MoniQA project [an EU project on analytical testing methods and protocols].”

No legal thresholds

In the absence of legal thresholds for the unintentional presence of allergens such as milk, peanuts and egg, many UK food manufacturers worked to unofficial limits or used the threshold-based Australian VITAL scheme as a guide when trying to validate cleaning regimes or test product samples for allergens, said Phil Goodwin from kit provider Diagnostic International. He added: “Having minimum requirements for validation of kits will hopefully make a big difference, as at the moment, everyone is using different validation protocols and different analytical standards.”

At Food Manufacture’s​ recent conference on allergen management, RSSL head of allergen services Simon Flanagan said the lack of thresholds made enforcement very challenging: “There was a recall recently on dark chocolate that contained milk. It did actually have a 'may contain' label but it was recalled anyway because it contained 'too much' milk. But how much is too much?”

The AOAC guidance will be published in the March/April issue of the Journal of AOAC International.

ELISA tests (biochemical kits used to detect the presence of allergenic proteins in samples), are widely used in food industry laboratories and by official bodies to detect and quantify allergens in foods.

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