Unformatted text preview: 3. QUICK-FREEZING IN LIQUID NITROGEN AND FREEZE-DRYING (LYOPHILIZATION)— these are means of preserving cultures, not of killing bacteria. HIGH PRESSURE Applying high pressure to liquid suspensions can inactivate vegetative cells by altering the molecular structure of proteins and carbohydrates. Endospores are relatively resistant. DESICCATION Desiccation or drying can kill microbe. Loss of moisture causes cells to either become dormant or die because there is insufficient water for cellular reactions to proceed. Species vary in their susceptibility. Dry surroundings kill some vegetative cells in one hour or less. Others can survive for months. Bacteria that produce endospores are extremely resistant to drying. Many viruses are also resistant to drying....
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- Fall '09