Both protein consumption and the world’s population are increasing, which leads to an urgent demand for sustainable protein sources. However, introduction of novel protein sources onto the food market is not without risk. Novel protein sources may induce new food sensitizations and allergies and elicit cross-reactive allergies in already allergic individuals. It is therefore pivotal that we can accurately assess the allergenicity of novel proteins. Several parameters have been proposed that can be used to assess allergenicity and regulate upon. The sensitizing potency of a protein would be an opportune parameter to regulate upon, but there are currently no assays available which can accurately predict the sensitizing potency of proteins. In this thesis, we showed that the prevalence of sensitization of a protein, which is relatively easy to determine for existing food proteins, could be used as a measure for the sensitizing potency. By using the prevalence of sensitization, test proteins can be selected that in turn can be used to develop and validate assays to assess the sensitizing potency of proteins. A reference set of existing proteins can then be established which can be used to compare the allergenicity of novel food proteins to. Additionally, we showed that evaluation of the gene expression of biomarkers in vitro could potentially be used to investigate allergenicity although another study indicated that digestion and transport can affect the reactivity of proteins and should be taken into account when developing in vitro methods to evaluate the sensitizing potency.