Food Allergy and Tolerance

What are allergens?

Food allergens can be defined as usually harmless food components or constituents which induce an allergic reaction in a sensitised individual. Food allergies affect about 1-2% of adults and 5-8% of children according to the FSA in the UK. Food allergy should not be confused with food intolerances such as lactose intolerance which is due to an inability to digest lactose or food poisoning from microbial contamination of food. The symptoms may be similar but the underlying causes are often different. Symptoms with varying degrees of severity include itchy or swollen lips, mouth, tongue and throat; skin reactions; wheezing or shortness of breath; diarrhoea, feeling sick, vomiting and bloating; coughing; a runny nose and sore, red and itchy eyes.


Over 160 foods/ingredients that cause allergies have been identified. These include:

  • Cereals containing gluten (wheat, rye, barley, spelt, kamut or their hybridized strains)
  • Crustaceas (e.g. lobster, crab, prawns and langoustine)
  • Eggs
  • Fish
  • Peanut
  • Milk
  • Nuts
  • Celery and Celeriac
  • Mustard
  • Sesame
  • Soy

Labelling & Legislation

For the allergic consumer it is particularly important to have full information about potential allergens contained in food products. This is why manufacturers must now follow the 2008 EU directive which requires all pre-packed foods sold in the Ireland containing certain allergenic ingredients or derivatives to be clearly labelled. See FSAI website for the latest legislative guidance (


Testing for the presence of allergens as part of an effective quality control process allows manufacturers to safeguard against undeclared allergens entering final products, thereby enabling them to comply with current labeling requirements.


Allergen Testing

ALS Life Sciences offer a range of allergen analysis – mostly through its fellow subsidiary laboratories ,  ALS Food & Pharma, in the UK and ALS Controlvet in Portugal. Testing for the presence of allergens utilises multiple techniques including Automated ELISA (enzyme-linked immunosorbent assay), PCR and chemistry for the detection of allergens.


ELISA techniques use antibodies to selectively target allergens or specific marker proteins within a food product for detection. Once the allergen has been selectively bound by the antibody an enzyme linked to these causes a proportional colour change. This change can be measured to give highly sensitive results. The technique is applicable to multiple sample matrices including environmental swabs. 


The advantages of this technique include:

  • The test is highly specific for the analyte.
  • The test is highly sensitive for the analyte.
  • The technique is more environmentally friendly as it does not produce large volumes of waste solvents.
  • Relatively rapid detection technique

PCR techniques require the extraction and amplification of target allergen DNA from samples. This test is highly specific but may not be representative of the quantity of allergenic protein content of a sample. This technique is highly useful when allergenic proteins are difficult to detect by ELISA. 


Allergen Test Methods:

  • Gluten ELISA
  • Casein ELISA
  • Peanut ELISA
  • Egg ELISA
  • Histamine HPLC
  • Sesame
  • Celery
  • Milk Components ELISA
  • Nuts PCR
  • Soya ELISA
  • Mustard
  • β-lactoglobulin
  • Sulphites (Sulphur Dioxide) 
  • Fish allergen
  • Crustacean
  • Mollusc
  • + Others upon request ELISA/PCR