Effects of freezing on microbes

- sudden death of some cells - portion of survivors die gradually during storage - reduction in microbial population: rapid at temp just below freezing, slows down at lower temps, very slow below -20C - dehydration of cells as water is converted to ice - increased viscosity of cytoplasmic material - loss of cytoplasmic gases (O2, CO2) - pH changes in cellular matter - protein denaturation (some enzymes damaged) - metabolic injury - temperature shock