Comparison of immunohistochemical, histochemical and immunochemical methods for the detection of wheat protein allergens in meat samples and cooked, dry, raw and fermented sausage samples

Abstract

Nowadays is it a common practice to add vegetable protein in the production of meat products. Because of the possible substitution of high-quality raw meat with vegetable protein without the labelling the product package and because of the allergenic potential of many vegetable proteins, it is important to develop accurate methods for its detection. The objective of the study was to compare histochemical, immunochemical (ELISA, ALERT gliadin screening test) and immunohistochemical methods for the detection of wheat protein in meat samples and sausages. Histochemical methods were useful for the detection of flour in meat samples, but the immunohistochemical method was better for the detection of wheat protein. ALERT gliadin screening test detected gliadin from 10 mg kg−1, while an immunohistochemical method detected wheat protein concentrations from 1 g kg−1 and an ELISA method detected wheat protein concentrations from 4 g kg−1. ALERT gliadin screening test showed results within 1 day, whilst an ELISA detection method took 2 days, and an immunohistochemical procedure took 5 days at the soonest, all including sample preparation. This study also focused on optimisation of an immunohistochemical method for samples of cooked sausage. In addition, three samples were sufficient for wheat protein detection at a concentration of 1 g kg−1 (and greater) with a confidence level greater than 95%.