Evaluation of two methods to identify the fraud of whey in fluid milk.
Gisele Olivieri, Letícia F.M.C de Aquino, Adriana C.O. Silva, Érica B. Santos, Celso F. Balthazar, Marion P.
da Costa, Carlos A. Conte Júnior, Eliane T. Mársico, Sérgio B. Mano. Faculdade de Veterinária,
Universidade Federal Fluminense – UFF, Rua Vital Brazil Filho 64, 24.230. 340. Niterói, Rio de Janeiro,
Brazil.
Addition of whey in fluid milk is a fraud and the detection of the minimum quantity of it was studied to
evaluate the accuracy of official method procedure (OM) and ultrasound. UHT milk was rigged with growth
concentration of whey (0%; 0,5%; 1%; 2,5%; 5%; 10%; 15%; 20%). Physical-chemical analyzes, such as
lipids, freezing point, density and non fat solids (NFS), was measured in all samples by official method and
ultrasound BOECO LAC 50®. There were detected difference in lipids in OM from 5% whey added in fluid
milk (P<0,01) and NFS from 2,5% (P<0,01); and lipids from 5%(P<0,001) in ultrasound detection. The
comparison of both methods shown significant statistic difference (P<0,05) only in lipids analyze from
control sample. Using official analytical procedures, there was a significant correlation in lipids (r=-0.9464)
and freezing point (r=-0,9360); by ultrasound, a significant correlation was in lipids (r=-0,9922), freezing
point (r=-0,9762) and NFS (r=-0,9763). It was suggested that failures exist in detection of addition whey in
fluid milk by both methods.