Allergen test may not accurately detect milk proteins triggers, warn researchers

Speaking at the recent National Meeting & Exposition of the American Chemical Society (ACS), Dr Joseph Baumert said the test that is usually used to detect milk proteins in processed foods may not work accurately with all foods types – sometimes missing proteins that could cause a reaction in people with milk allergies, which are among the most common of all food allergies.

Baumert said thermal and non-thermal processing of foods can change the proteins responsible for milk allergy in ways that make them difficult to detect using a standard enzyme-linked immunosorbent assay (ELISA) test.

He explained that manufacturers and food-safety agencies use the ELISA tests to ensure that food-processing equipment and finished products are free of allergens – or are labelled with appropriate warnings.  

However, Baumert noted that thermal changes to milk proteins from processing could change them enough to mean they go undetected by the allergen test, but may still cause allergic reactions.

“The results of these studies could be utilised by commercial ELISA kit manufacturers to aid in improving ELISAs for detection of milk residue in processed food products. These improved tests can be adopted by the food industry, if necessary, to allow for reliable detection of milk residue regardless of the type of processing that is used,”​ he said.

However the expert said that the improvements to allergy tests “should not result in commercial tests that are more expensive or difficult for food processors to use.”​

Protein triggers​

Baumert, from the University of Nebraska-Lincoln, USA, explained that heating and other processing of foods can make milk proteins change their shape or structure.

Such structural alterations can affect the ability of the antibody’s used the ELISA test to bind to milk proteins. But he said that the alterations in the protein structure do not necessarily mean that they become non-allergenic – warning that such alterations can lead to proteins structures that are not detected by the test but are allergenic for the majority of milk-allergic individuals.

The research team came to their conclusions after studying how ELISA tests performed on several measures of accuracy when allergenic milk proteins were structurally altered in foods that are processed by boiling, baking, frying, or being heated in other ways.

Baumert said the results could help the food-processing industry and ELISA manufacturers make changes that better protect consumers with milk allergies – adding that that other scientists are performing similar research on other common foods allergens like contain eggs and peanuts.