Taking the ambiguity out of allergen management

By Kendall Baker

- Last updated on GMT

Kendall: 'Tests are not always black and white – know what questions to ask'
Kendall: 'Tests are not always black and white – know what questions to ask'

Related tags Regulation Food safety Packaging & labelling

Allergens have long been one of the most prevalent food safety topics for consumers, hospitality businesses and food industry professionals alike.

Even more so in recent years due to the tragic events that triggered the introduction of Natasha’s Law - the new labelling legalisation relating to pre-packed for direct sale (PPDS) foods that will be enforced in England from October 2021. The current legislation does not require every allergen and ingredient to be listed on individual freshly prepared products, but instead it just needs to be available upon request, Natasha’s Law changes this. 

Though this is a great step forward in the café and deli industry, where PPDS foods are typically sold, there is still so much more to consider when it comes to allergens and public safety throughout the entirety of the food industry. 

With 14 recognised allergens to consider, having a better understanding of ingredients, processes, testing and limitations would be of great benefit to any food enterprise looking to protect their customers (foremost) as well as their business from financial and reputational damage in relation to allergens.

Factors to identify risk

Considering the ingredients list and where the raw materials are processed or produced, and the chances of incidental or even intentional substitution are important factors to identify risk and subsequently inform a programme for testing.

Garlic is a good example. It is a root crop and has often been grown in rotation with peanuts (groundnuts). Peanuts are a legume and are used for fertility building so work well in rotation with garlic – however, it introduces an additional (unexpected) risk with garlic. Turmeric (another root crop) can also be grown or rotated with peanuts. Understanding production risks upstream is important in assessing risk. Where is your material coming from? What risks are associated with this? 

Testing is an excellent tool in the defence against allergen control but arbitrary uninformed off the shelf testing isn’t always enough to ensure good practice and protection. Understanding the allergenic proteins, the testing and cross-reactivity limitations can help avoid misinformed decisions. Minor exposure to peanut can be fatal for some allergy sufferers and therefore the food industry must source the most sensitive test kits, but cross-reactivity with other related species needs to be understood.

Conflicting results

At Food Forensics we got frustrated with conflicting results from different laboratories so set out to understand what was causing the difference in results. We brought two different ELISA instruments to run alongside our PCR and Next Generation Sequencing (NGS). We sourced multiple commercial kits from a range of commercial providers. All the tests declared some cross reactivity (although some just declared a list of ingredients the test did not​ cross react with).

With known​ samples all test kits performed well, we saw little difference between the performance of the different instruments and the results were not analyst dependant. Tests were selected based on the declared ingredients to avoid known cross reactivity. But, with test samples things got interesting. We started to see positives in some kits and not in others. We used our Next Generation Sequencing capability to see what was in the samples causing the issues. Bingo! Undeclared ingredients which had known cross-reactivity with some of the kits but not others.

 So, we have 2 issues.

  1. False positives caused by cross reactivity with undeclared ingredients. In most laboratories these samples would have been reported as a positive. As the manufacturer/food business you would then be facing the implications of an undeclared allergen with all that entails.
  2. Undeclared ingredients

Undeclared ingredient

While the good news is you did not have peanut present, you have identified another issue: an undeclared ingredient. This then needs to be risk assessed, investigated and appropriate action taken. However, depending on what the undeclared ingredient is the immediate implications are considerably less severe. 

Food Forensics now runs several peanut kits with different claimed cross reactivities. Test kits are selected on the basis of declared ingredients. If we have a positive on one test, to rule out cross reactivity, we immediately rerun on another kit with a different set of cross reactivity. If these both return positive, we report a positive. If, on the second test, the sample reports a negative, we recommend running through NGS to understand what ingredient is present causing the cross reactivity. 

Tests are not always black and white – know what questions to ask.

Kendall Baker is scientific lead at Food Forensics

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