 An "autoclave" is a type of pressure cooker used by laboratories and hospitals to sterilize equipment.Large pressure cookers are often called "pressure canners" in the United States, because of their capacity to hold jars used in canning.Pressure canners are specifically designed for home canning, whereas ordinary pressure cookers are not recommended for canning due to the risk of botulism poisoning, because pressure canners hold heat and pressure for much longer than ordinary pressure cookers; these factors are a critical part of the total processing time required to destroy harmful microbes.