Detection of celery (Apium graveolens), mustard (Sinapis alba, Brassica juncea, Brassica nigra) and sesame (Sesamum indicum) in food by real-time PCR

Legislation requires labelling of foods containing allergic ingredients, amongst them celery, mustard and sesame. Here we present robust quantitative and sensitive methods for real-time PCR detection of celery, mustard (Sinapis alba and Brassica sp.) and sesame in food. The development of the DNA-based assays was part of an effort to generate alternative detection methods for allergens for which effective protein-based assays are lacking. The celery and sesame methods were specific for the celery mannitol dehydrogenase gene and the sesame allergen encoding 2S albumin gene, respectively, when tested against a range of plant materials. The mustard method was specific for the allergen encoding sinA gene and its homologues present in different Brassica sp. All primer probe pairs gave high amplification efficiency and sensitivities below approximately ten molecules of purified template DNA. These DNA-based detection methods will constitute supplementary and complementary methods to the traditional protein-based methods. Laboratories may choose different analysis formats depending on the food matrix, the availability of specific tests and the performance characteristics of the tests.