The three-dimensional structural properties of allergens control their allergenicity. Thermal processing of proteins and carbohydrates brings major changes in allergenicity. School systems have protocols about foods with potential allergenicity. Regulatory authorities require that new modified foods be tested for allergenicity before they are marketed. Thorough cooking may eliminate the allergenicity. However, there is controversy on contribution of "A. penicillioides" to allergenicity of "Dermatophagoides pteronyssinus".