Detection of Undeclared Peanut, Milk and Egg Allergen using Immunological Method and Confirmation of Peanut, Milk and Egg Proteins using LC-MS/MS

Abstract

The prevalence of food allergies is approximately 4% of adults and 6% of children in the general population, increasing worldwide, and food allergy incidents due to processed foods are occurring every year. Since the most obvious management methods for food allergy are to avoid intake of allergenic ingredients, so patients with food allergy carefully identify allergen-inducing substances on the food label when they purchase. However, processed foods may contain allergenic ingredients not listed on the food label due to unintentional incorporation, non-sanitary working conditions, incorrect labeling and cross contamination between food products, which can lead to serious problems for sensitive individuals with food allergy. In this study, three of commercial ELSIA kits were used for the detection of undeclared peanut and milk proteins in processed products. Four of the total 105 products that did not contain peanuts on the label were found to be positive in test for peanut proteins, while six of the total 76 products that did not contain milk on the label showed positive results in the milk allergen test. Three of the four in which peanut protein were detected showed conflict results when three different ELISA kit were used. In the case of milk, all the six food products in which milk proteins were detected showed the same positive results with ELISA kits. To confirmation the existence of undeclared proteins were tested using LC-MS/MS methods. Food products with conflicting results with commercial ELISA kits were chosen and conformational LC-MS/MS experiments were performed. Four peanut-specific peptide sequences in three products with undeclared peanut proteins were confirmed with LC-MS/MS experiments. Ten egg-specific peptide sequences in four food products with undeclared egg proteins were detected with LC-MSMS experiments. Although several peptide sequences have been identified in milk detection products, they were not milk specific peptides because these peptides were also found in other food proteins such as wheat, soybean, egg and walnut. So, these peptides which founded in product with undeclared milk proteins were not considered as milk-specific peptide. The LC-MS/MS method could be acquired to confirm conflicting results with commercial ELISA kits for detection of undeclared allergens in processed foods.