Dough containing, valved package

The combination of dough product based on a low temperature inactive living yeast which generates gas over time, the dough product containing between 43 and 62% of flour, between 5 and 23% fat, between 0.01 and 1% of a low temperature inactive strain yeast that is essentially inactive at temperatures up to 8-12° C., between 1.0 and 2.5% of sodium chloride or sugar, and between 23 and 33% water, and a closed packaging system containing said dough product, said packaging system comprising a housing of a material which is essentially impervious to oxygen, valve means operatively associated with the housing for allowing exit of gas from the housing when the gas pressure exceeds a certain minimum value and which closes when said gas pressure drops below the minimum value to prevent entry of oxygen into the housing, and a substantially oxygen-free gaseous atmosphere surrounding the dough product and additional to any gases generated by said living yeast.