Studio e validazione di metodi di biologia molecolare per l'identificazione di specie in matrici alimentari

In contemporary societies, consumers' choices in terms of food does not simply reflect the need to meet their nutritional needs, but also their lifestyle, their religious beliefs (for ex. the lack of pork for Jews and Muslims) or health problems that afflict them (for ex. the absence of peanuts, gluten or lactose for people with allergies) (Musto, 2006). The mismatch between what is said and what is actually present in the product purchased is a food fraud. The correct identification of species represents a crucial point in the control of food quality in order to avoid fraud. Today, the analysis of the gene encoding the cytochrome b has been universally adopted to identify animal species.The method used and validated in the identification of species in foods in this work is a PCR-Multiplex, that is an end-point PCR built of multiple sets of primers in a single mix to produce amplicons. These are of various sizes and specific for different target DNA sequences. This method allows you to simultaneously amplify different segments of the same gene of interest using the different primers pairs. By targeting many species in a single PCR experiment, the necessary information can be acquired by a single test that would otherwise require the use of more reagents and more time for the execution. Have been the subject of study the following meat matrices: burgers, sausages (fresh and dried), kebabs, meatballs and wurstel. The DNA was isolated by the use of the QIAamp DNA Mini kit (Qiagen), according to the guidelines given by the manufacturer. DNA was quantified by reading biofotometrica (EppendorfBioPhotometer). The extract was then subjected to amplification by the use of specific primers. The PCR products were analyzed with QIAxcel (Qiagen): an advanced, fully automated capillary electrophoresis. Were analyzed 51 samples: all, but two, were found to conform to the label. In the first sample does not comply (a hamburger) said only cattle, pork traces were found. In the second sample does not comply (a wurstel) said cattle and pig, chicken traces were found.One future development of such tests will be the development of a Multiplex Real Time PCR, in order to quickly test the samples both from a qualitative and quantitative point of view.