Studying the Effects of Heat and Cold Shock on Cell wall Microstructure and Survival of Some LAB in Milk

In this study we investigated the effect of heat shock (42-45°C for 5, 10, 15, 20, 25, 30 minutes) cold shock (4, 0, -5, -10 and -20°C for 2h) on cell wall Microstructure of LAB. Cell wall Changes and micro -damage behavior of LAB under the impact of heat and cold shock was studied by optical microscope and Transmission Electron Microscope (TEM). Treatment of LAB with heat and cold shock had significant effects on permeability properties of LAB just in long heat exposures and very cold temperatures. The survival of LAB was just affected by the heat shock.