Effect of high pressures on Streptococcus salivarius subsp thermophilus

The effect of pressurization (400 MPa/30 min) on survival rate of 7 bacteri al strains of Streptococcus salivarius subsp. thermophilus was studied. It was found that the degree of bacteria inactivation was dependent on the str ain and, varied from 35,3 to 99.9%. In case of the pressure-most sensitive bacteria, their number was decreased by 3-5 size orders. Pressurization may change metabolism of bacteria by limitation of their capacity of biosynthe tizing lactic acid. It seems that prolongation of the shelf-life of yoghurt by the high pressure processing may be obtained by complete inactivation o f lactic acid bacteria or by the change of their metabolism.