Samples of uninoculated batter of a typical Hungarian fermented pork sausage with or without regular NaCl and nitrite additive, and similar samples but heavily inoculated with Listeria monocytogenes have been treated by high hydrostatic pressure (HHP) of 600 MPa for 20 min and reduction of the viable cell count of the test organism was selectively estimated. The HHP treatment caused 5 log-cycles reduction of Listeria count in the salt-free batter and around 4 log-cycles in the salt-containing samples. Discolouration of the batter as an effect of the high pressure treatment was observed. It was less pronounced in the nitrite-containing samples. The HHP reduced softness of the batter and changed drastically the pattern of its DSC thermogram pointing for significant protein denaturation.