SOY PROTEIN DETECTION IN COMMERCIAL ARGENTINE MEAT PRODUCTS USING IMMUNOCHEMICAL METHODS.

CELLERINO KARINA; BINAGHI MARIA; CAGNASSO CAROLINA; DOCENA GUILLERMO H.; LÓPEZ LAURA

Montreal

Congreso; 7th Workshop on Food Allergen Methodologies; 2012

The Argentine Food Code will promptly incorporate the mandatory declaration of allergens in food labels.Therefore analytical methods for the detection of allergens in food products should be available. Soy components are frequently used in meat products because of the functional properties of soy proteins. The aim of this work was to evaluate the performance of different immunochemical methods for  the detection of soy proteins in commercial meat products as well as in raw model systems of bovine meat or cooked model systems of boneless ham added with soy isolated. Seven raw model systems of bovine meat  with 10- 2000 ppm of soy isolated and  7 cooked model systems of boneless  ham with 10-2000 ppm of soy isolated were analysed. Besides, 7 commercial meat products were analyzed. Most of them  do not declare soy products in their labels. Samples were analyzed by Dot Blot and Immunoblotting with specific polyclonal serum against soy proteins and ELISA using the Veratox quantitative soy allergen kit from Neogen. Dot Blot and Immunoblotting methods detected 100 ppm of soy isolated in raw and cooked model systems, while the Neogen kit detected 250 ppm. In the model systems which were added  less than 250 ppm of soy isolated  the ELISA kit was negative. There was  a wide difference between the quantitative results obtained by ELISA and the real values. Dot Blot and Immunoblotting were positive in 4 commercial meat products while they were negative in the other 3 products. In 3 of the positive samples the results of the ELISA method were higher than 20 ppm of soy isolated, while in the fourth positive sample the result of the ELISA method was less than 10 ppm of soy isolated. ELISA results were less than 10 ppm of soy isolated in samples where Dot Blot and Immunoblotting results were negative. In conclusion Dot Blot and Immunoblotting methods using soy specific polyclonal serum resulted a more sensitive analytical method than the ELISA kit tested. All methods detected soy proteins in 3 products that did not declare the presence of soy in the composition. An additional product wich was not labeled as containing soy, was positive by Dot Blot and Immunoblotting methods while it was negative by ELISA.