New research has found that pasteurised raw egg contains the same main allergens as fresh raw egg, and is therefore still the safest option for testing for allergies.
Researchers from the University of Adelaide in South Australia compared the properties of pasteurised with non-pasteurised raw egg in order to better understand if pasteurised egg could be tolerated by allergic children.
Pasteurised raw egg, in which the egg is heated just enough to kill bacteria, is used in allergy testing with children because of the risk of salmonella or avian influenza from fresh raw egg.
Researchers have been concerned that the two forms of egg couldn't be accurately compared because the pasteurisation and drying process was likely to change the structure of the egg protein.
"Heating of any kind has the potential to affect the allergenic properties of egg protein, which is why we needed to understand the differences between these two types of raw egg," said University of Adelaide PhD student Merryn Netting from the University's Women's and Children's Health Research Institute.
"In our laboratory tests, we discovered that in fact the pasteurised raw egg contains all of the main allergens and is similar to unpasteurised raw egg. The way it is digested also appears to be the same," said Netting.
Associate Professor Michael Gold, research leader in Allergy and Vaccine Safety with the University's Robinson Research Institute, said egg allergy is the most common food allergy in Australia, affecting 9 per cent of young children.
"All egg proteins have the potential to induce an allergic reaction. The main form of egg that children with allergy can often tolerate is heated at very high temperatures, such as through the baking process," said Associate Professor Gold.
"Oral food challenges under strict medical supervision are important for diagnosis and management of egg allergy in children. This discovery means that pasteurised whole raw egg powder is now confirmed as a suitable substitute for raw egg, and we can continue to use it in clinical practice."
Netting said that the finding means that studies into egg allergies and tolerance in children are as accurate as they can be.
"It also means that no matter which form of raw egg is used, the main allergens are there - so from an allergic child's point of view, no form of raw egg is necessarily 'safe'," she said.
The results of this study are published in the journal Pediatric Allergy and Immunology.