Almond Allergy: An Overview on Prevalence, Thresholds, Regulations and Allergen Detection

Abstract

Food allergy has been on the increase for many years. The prevalence of allergy to different foods varies widely depending on type of food, frequency of consumption and geographic location. Data from the literature suggests that the prevalence of tree nut allergy is of the order of 1% in the general population. Almond is one such tree nut that is frequently eaten in many parts of the world and represents a potential allergenic hazard. Given the need to label products that contain allergens, a number of different methods of direct and indirect detection have been developed. However, in the absence of population-based threshold data, and given that almond allergy is rare, the sensitivity of the required detection is unknown and thus aims as low as possible. Typically, this is less than 1 ppm, which matches the thresholds that have been shown for other allergens. This review highlights the lack of quantitative data on prevalence and thresholds for almonds, which is limiting progress in consumer protection.

Almond allergens: update and perspective on identification and characterization

“…83 It was considered to be an almond allergen and called Pru du 2. 77,78,83 However, as for almond PR-10, we could not find any immunological characterization of almond PR-5. Thus, almond PR-5 may be an allergen because it has very high sequence identity with the peach allergen Pru p 2, 19,90 although immunological experiments or food challenging data are needed to confirm this.…”

“…Pru du γ-conglutin Almond γ-conglutin was considered as an almond allergen 64,77,78 because it was reported that the N-terminal sequencing of a 45-kDa IgE binding protein resulted in a sequence of 25AA that had 40% identity with the 45-kDa mature γ-conglutin of white and narrow-leafed lupine. 64 To our knowledge, no additional information about this almond protein is available.…”

“…Pru du γ-conglutin was also listed as a 7S vicilin storage protein as a member of the cupin superfamily, 77,78 although γ-conglutins are not vicilins. Conglutin-γ shares sequence and structural similarities with xyloglucan-specific endo-beta1,4-glucanase inhibitors, although no glucanase inhibitor activity was associated with a natural γ-conglutin as a result of cleavage of the protein by peptidase digestion.…”

“…83 It was assumed be an allergen and called Pru du 1. 77,78,83 To our knowledge, however, immunological characterization of almond PR-10 is lacking, although it has very high sequence identity with peach PR-10 which is a food allergen known as Pru p 1. 19,84 Thus, we consider that almond PR-10 is very likely to be an allergen, and we hope that immunological experiments or food challenging data of almond PR-10 will be collected in the near future.…”

“…The 2S albumin has been listed as an almond allergen using the name Pru du 2S albumin. 77,78 To our knowledge, however, there are no data in the literature that characterized almond 2S albumin as an allergen, except when two short, partial peptide sequences of Pru du 8 were misconstrued to be those of a 2S albumin. 64 Nevertheless, the 2S albumins are a major group of seed storage proteins in many dicotyledonous plant species.…”