For certain types of food it's easy to understand if the food contains allergens, like yoghurt or dairy products that are made up of/or derive from milk - one of the most common allergens.

However, other more prepared types of food can also contain allergens as a secondary “hidden” ingredient and it is therefore difficult to understand if they too, contain allergens or not.

Milk is often “hidden” in many types of more elaborated food like canned tuna, which can contain casein, a protein in milk used to increase the yield. Crumbed meat or meatballs, where milk often is used as a thickener, is also a type of food where allergens can be found. Meat can be particularly “ treacherous”, especially when it's prepared in a restaurant, where they often use butter, another dairy product, to enrich the flavour.

Wheat flour is another ingredient which often is used during the preparation of food, because of its ability to mix the different ingredients and enrich the flavour. Therefore, it's important to pay attention to crumbed meat or fish but also to some kinds of hotdog and certain types of ice-cream.

Other types of food which normally do not contain allergens can be prepared with “contaminated” utensils normally also used to prepare food containing allergens. If the utensils are not cleaned properly before and after use, allergens may easily be transferred from one food to another.

Food slicers are common sources of allergens because they are often used to slice cheese and meat, food that contains milk protein. Kneading machines, used to prepare whole wheat pasta and pasta including eggs, are other sources which spread allergens.

Food allergens can also be found in other types of food like egg whites, containing a protein which is able to stimulate the production of Hyaluronan, a substance that helps to keep the skin soft and elastic. Therefore this protein is often found in make-up, shampoo and medicines.

Other medicines can contain lactose, an allergen found in milk used as an added substance (excipient) to the main ingredient of the medicine.

A product or a type of food which appears harmless can maintain “hidden” allergens. Carefully reading products labels one can understand if the food contains allergens or not. So, give a good look at the labels and in doubts consult the manufacturers directly.