The diagnosis of food allergy, as assessed by skin tests or in vitro tests with allergen extracts, has insufficient diagnostic performance and needs to be confirmed by food challenges. However, the availability of molecular allergens (recombinant or highly purified) for laboratory methods has profoundly changed the diagnostic approach to food allergy. In fact, the allergy diagnosis conducted at the molecular level, which is defined internationally as component resolved diagnosis (CRD), allows to characterize more precisely the sensitization profile of the individual patient, distinguishing the sensitizations to allergens that are strongly associated with a given source (genuine sensitizers) from those to molecules that are common to many sources (panallergens) or cross-react with other components from the same family or from other families. This review provides an update on the allergen molecules from foods, including plant foods and animal foods, and on the techniques to detect them, by means of a single reagent (singleplex) or an array of molecules tested at the same time (multiplex). Such testing offers detailed information on the sensitization profile of patients and enables the physician to suitably manage their allergy. Moreover, identifying the real causative allergens will be crucial when allergen immunotherapy for food allergy will be introduced in the near future. We also address patents concerning food allergens in this review.