A pressure canner is a specialized kitchen appliance used for preserving low-acid foods, such as vegetables, meats, and poultry. It operates by sealing food in jars and using steam pressure to raise the temperature above boiling point, effectively killing harmful bacteria and ensuring safe preservation. Using a pressure canner is essential for home canning, as it helps prevent foodborne illnesses. Unlike water bath canning, which is suitable for high-acid foods like fruits and jams, pressure canning is necessary for safely processing low-acid foods to avoid the risk of botulism, a serious food poisoning caused by Clostridium botulinum bacteria.