D1.196 - Characterizing the detectable milk protein allergens in milk ladder foods

Cow’s milk allergy (CMA) is a complex presentation of food allergy, often encountered during infancy and early childhood. Recent data indicates that milk ladders may be a suitable strategy for the reintroduction of cow’s milk in CMA. To improve the safety and standardization of milk ladders, an understanding of the milk proteins in the ladder foods is required. 

The enzyme-linked immunosorbent assay (ELISA – IgG test) was chosen to detect milk protein content of milk ladder foods as it can quantify the level of a specific protein, whilst relying on the conformation of the protein which may change with heating. Cookies (step 1), muffins (step 2) and pancakes (step 3) were prepared according to the recipes and methods in the iMAP ladder (published in 2017. Three batches of each food were made by the same person, using the same kitchen equipment but cleaned between preparations to avoid any contamination. Additionally the iMAP ladder also includes cheese (step 4) , yogurt (step 5) and milk (step 6). Three lots of commonly eaten brand of yoghurt, cheese and milk were bought at a local store in the USA and were: Stonyfield Whole Milk Plain Yogurt, Tillamook Medium Cheddar Cheese, PET Pasteurized Whole Milk and UHT milk Horizon Organic UHT Whole Milk. Raw, unprocessed milk was acquired from BioChemed Services (Virginia, USA).

In the cookie (step 1), quantities of milk protein detected per serving were the lowest, with the density of the food matrix potentially having an impact. In our analysis, the levels of bos d5 (b-lactoglobulin) measured in pancakes (step 3) per serving were lower than iMAP muffins (step 2, the step prior to pancakes). Levels of bos d5 (b-lactoglobulin) in yoghurt were also lower than cheese. Cheese (step 4) is currently indicated as the step in the iMAP ladder before yogurt. Levels of bos d11 (b-casein) detected did not follow a general increase across the ladder. For the cookie, iMAP muffin and pancake levels of bos d11 were not significantly different for the suggested starting portion sizes (1, ½ and ½ respectively). Similar to bos d5, the levels of bos d11 were much higher in cheddar, likely due to the high proportion being casein (Table 1).

We have shown that the order of milk ladder foods is different depending on whether it is based on calculated protein amounts, measured levels of bos d5 or measured levels of bos d11.  HCPs need to be aware that depending on which protein is tested, ladder foods have a different order.