Technical Abstract: No legislation or regulatory efforts have been put in place to establish standardized methods for food allergen extract preparations that are used for purposes ranging from diagnostic skin prick test (SPT) and Radio Allergrosorbent Test (RAST), to standards for detection methods. Our findings suggested that the structural and functional changes due to food processing contribute to increased allergenic properties of peanut proteins, and may indeed enhance the possibility of becoming sensitized to peanuts. However, the majority of these analyses were carried out in vitro with the exception of mouse sensitization experiments. Therefore, in order to determine if roasting influences the immunogenic properties of differently processed peanuts in humans, skin prick tests (SPT) were performed on peanut allergic and non-allergic patients. Also, additional in vitro analyses were carried out to determine the contribution of structural changes to immunogenicity in allergic patients. We found that commercially available SPT extracts for peanut and other foods are often, 1) not processed in the form that they are ingested, and 2) variable among companies that produce them, and therefore, can result in misdiagnosis of allergic patients by physicians. It is important to develop standardized food extracts for various diagnostic tests such as SPT and RAST in addition to reagents used for detection of allergen cross contamination in food.