David Reading reminds corporate members how serious allergy to cow’s milk can be, and reports on the latest findings with regard to thresholds and reference doses.

A ten-year-old boy took one bite of a pre-packed apple dessert and suffered anaphylaxis. It transpired that the pie contained 0.006 per cent milk protein. It had been correctly labelled, but the boy – who knew he was allergic to cow’s milk – made a mistake and did not check. Fortunately he recovered thanks to prompt medical treatment. A six-year-old girl suffered a severe reaction in a restaurant to an ice cream labelled as “non-dairy”. After the girl recovered, enquiries revealed that a major ingredient of the ice cream was skimmed milk. These two cases – taken from our files – demonstrate clearly how serious milk allergy can be. Although allergy to peanuts and tree nuts is still frequently in the news, it must not be forgotten that other foods are occasional causes of anaphylaxis.

Cow’s milk allergy is one of the most common food allergies in the UK and throughout the world. The first adverse reactions to cow’s milk were described 2,000 years ago, but it was only in the mid to late 20th century that research groups began analysing of cow’s milk allergens. The completion of our recent fact sheet on cow’s milk allergy reminded us how complex this subject is.

Immediate allergic reactions to cow’s milk – sometimes referred to as “a true allergy” – are just part of a wider picture. Helpline staff working for food companies should, perhaps, be aware that customer complaints of “allergic” reactions to milk may have other causes. Immediate cow’s milk allergy – fairly common among children – is well understood by doctors. It occurs when the body’s immune system wrongly perceives some of the proteins in cow’s milk to be a threat and, as a result, produces antibodies of the Immunoglobulin E class (known as IgE for short). These antibodies are specifically targeted against one or more of the cow’s milk proteins.

Subsequently, whenever the person with the allergy comes into contact with milk, these antibodies trigger certain chemicals such as histamine to be released from special immune system cells in the blood and tissues where they are stored. It is the sudden release of these chemicals in the body that causes the symptoms. Symptoms can be mild but for some there is a potential for anaphylaxis.

However there are numerous other conditions triggered by milk, making the overall subject much more complex. These include:

• Delayed cow’s milk allergy (non-IgE milk allergy)
• Cow’s milk-induced proctocolitis
• Cow’s milk protein-induced enteropathy syndrome
• Eosinophilic Gastrointestinal Disorder (EGID)
• Food protein-induced enterocolitis syndrome (FPIES)
• Lactose intolerance

To find out about immediate cow’s milk allergy and these other conditions click here.

The question the food industry will be asking relates to labelling: What is the level of cow’s milk beneath which the risk of an allergic reaction is negligible and Precautionary Allergen Labelling (PAL) is not required? The answer is that scientific studies have reached firm conclusions on this. In 2011, the VITAL Scientific Expert Panel (VSEP) was tasked with identifying reference doses for allergens by the Allergen Bureau of Australia-New Zealand. It was able to access the results of 17 published studies, as well some unpublished data, encompassing in total 351 food challenges, most of them in children.

This data was sufficient to define a robust reference dose of 0.1mg of milk protein per serving, which would protect 99% of those with a milk allergy against any reaction (Taylor et al 2014). As was done successfully with peanut, challenges with single doses of milk (protective of 95% rather than 99%, for statistical reasons) are currently underway to validate the milk reference dose.

Another key question is: Is there any sign that regulators are reaching the point when they can offer robust guidance to the food industry on action levels? The answer is that while regulatory bodies have welcomed the proposed reference doses (for milk and other allergens) as a major step forward, formal adoption has been much slower. Authorities in Belgium and Germany have produced documents supporting their use in allergen management. Anecdotally, other regulatory authorities have used them as a starting point for their risk assessment and management actions.

In the UK, the Food Standards Agency is supportive and insists that the use of PAL must be based on a thorough risk assessment. A current initiative to bring allergen management within the ambit of the Codex Alimentarius, with which the FSA is actively involved, may also help to move things forward in the future.

References

Taylor SL, Baumert JL, Kruizinga AG, Remington BC, Crevel RW, Brooke-Taylor S, Allen KJ, Houben G (2014). Establishment of Reference Doses for residues of allergenic foods: Report of the VITAL Expert Panel. Food Chem.Toxicol. 63, 9–17.

AFFSCA (2017) Avis 24-2017: Doses de référence pour les allergens. http://www.afsca.be/comitescientifique/avis/2017/_documents/Avis24-2017_SciCom2017-01_dosesdereferenceallergenes.pdf {In French with English summary}.