Long-shelf-life pasteurization yoghourt and preparation method thereof

The invention relates to yoghourt, in particular to long-shelf-life pasteurization yoghourt and a preparation method thereof, which are characterized in that after milk pretreatment is carried out, a mixture of colloid and sugar (with the weight ratio of the colloid to the sugar of 1/(0 to 100)) is added into the milk, then, obtained materials are homogenized, the pasteurization is carried out, after the obtained materials are cooled, strains are added into the obtained materials for fermentation, and the filling is carried out after the sterilization to obtain the products of the invention, wherein the milk can be fresh milk or reconstituted milk, wherein the colloid addition has the weight part proportion of milk/colloid=(95 to 99.9)/(0.1 to 5), wherein the colloid has the ingredients and the weight part proportion of starch/sodium alginate/agaragar=(0.5 to 90)/(0.1 to 5)/(1 to 15). The colloid used in the method of the invention carries out experiments for many times by the inventor. After the colloid of t