botulism a rare but very dangerous form of food poisoning caused by a toxin produced by the bacterium Clostridium botulinum. This organism is widespread in the environment, for example in river mud. It is anaerobic—that is, it functions only in the absence of oxygen—and will not grow in an acid medium; but it can survive unfavourable conditions by forming spores. These withstand high temperatures and can persist in cooked meat (the name botulism is derived from the Latin botulus, a sausage, because of incidents involving such foods) and non-acid canned vegetables, if these have not been prepared properly. To kill all spores food must be heated to 121 °C (250 °F) for three minutes, which is possible only in a pressure cooker or a commercial autoclave.