Effetti dell'introduzione di innesto selezionato di microrganismi caseari autoctoni sulle caratteristiche del formaggio DOP Bitto

The research originates from the need to improve our knowledge of the autochthonous microflora of milk used for the production of Bitto cheese in order to have a starter that could improve the production and reduce the occurrence of defects. Bitto is a PDO cheese from Lombardia region, produced only during the summer period in the alpine area, mainly in the province of Sondrio. Ninety seven strains of lactic acid bacteria were isolated from curds obtained from milk coming from four area in the Alps. Three strains were selected to make two starter mixtures, with different acidification ability, subsequently tested in the Bitto production. Cheeses obtained were evaluated by a panel of assessors and analysed for their chemical and volatile fraction composition. The same determinations were carried out on 45 Bitto cheeses sampled from among those participating in an exhibition that takes place in Morbegno (Sondrio province) every year. Considering the above parameters, the cheeses obtained with the use of starters showed values that fall within the ranges obtained for Bitto cheese, showing that the use of starter mixture does not affect the characteristics of the product. Moreover, it was possible to distinguish among the experimental cheeses according to the producer: this result shows that, despite the use of the same starters, the identity of each producer remains preserved.