Cheese species specific identification and adulteration detection by RFLP-PCR

POSIK D.M.; PERAL GARCÍA P.; GIOVAMBATTISTA G.

Cordoba, Argentina

Congreso; III Congreso Internacional de Ciencia y Tecnología de los Alimentos; 2009

Ministerio de Ciencia y Tecnología de la Provincia de Córdoba

The importance of food species specific identification has grown during the last years due to economical, health, religious and conservation factors, among others. In this scenario, researchers develop molecular techniques based in DNA in order to identify species in food. Adulteration of food is common mainly by economic reasons, for example the substitution of high commercial value species as raw materials by others of inferior costs. These practices are not only a fraud to consumers but also constitute a serious health menace. A case study is analyzed in this work. An allergic person to cow milk bought a corrupted goat cheese, as consequence of it consume the person suffered a strong allergic reaction. This led him to demand the cheese producer, and a sample of this cheese was submitted by the Buenos Aires Province Justice to the Domestic Animal Genetic Service (GAD-IGEVET), with the aim of determine the origin species of the components used in its manufacture. Total DNA was obtained from the sample by means of the silica oxide and guanidinium tiocianate method. A 358 bp fragment corresponding to a of citocrome b gen was amplified by PCR and was digested with Hinf I and Hae III restriction enzymes. Band pattern generated allow differentiate the main Argentinean milk species (cow, goat and sheep) and control samples from cow and goat DNA were analyzed. The comparison of band patterns shows that the cheese has a complex pattern product of the superposition between the cow and goat restriction fragments. By this method we demonstrate that the doubtful cheese, commercialized as pure goat, was adulterated with cow milk in an important proportion. The obtained evidence strongly supports the public prosecutor accusation.