Botulism is a rare, life-threatening paralytic illness caused by neurotoxins produced by an anaerobic, gram-positive, spore-forming bacterium, Clostridium botulinum. Bacterial growth is inhibited by refrigeration below 4° C., heating above 121° C, and high water-activity or acidity. And although the toxin is destroyed by heating to 85° C. for at least five minutes, the spores formed by the bacteria are not inactivated unless the food is heated under high pressure to 121° C. for at least twenty minutes.
The incidence of foodborne botulism is extremely low. This danger includes a mortality rate of up to 65% when victims are not treated immediately and properly. Most of the botulism events that are reported annually in the United States are associated with home-canned foods that have not been safely processed.
Follow proper canning instructions. Inspect the canning container for any leaks, bulges, cracks, or damages. If they are present, do not consume the product. If the container spurts liquid or foam when opened do not consume the product. Discard the food if it has a spoiled smell, color, or texture. When in doubt, throw it out.
After their ingestion, botulinum neurotoxins are absorbed primarily in the duodenum and jejunum and pass into the bloodstream and travel to synapses in the nervous system. There, the neurotoxins cause flaccid paralysis by preventing the release of acetylcholine, a neurotransmitter, at neuromuscular junctions, thereby preventing motor-fiber stimulation. The flaccid paralysis progresses symmetrically downward, usually starting with the eyes and face, then moving to the throat, chest, and extremities. When the diaphragm and chest muscles become fully involved, respiration is inhibited and, unless the patient is ventilated, death from asphyxia results. Classic symptoms of botulism include nausea, vomiting, fatigue, dizziness, double vision, drooping eyelids, slurred speech, difficulty swallowing, dryness of skin, mouth, and throat, lack of fever, muscle weakness, and paralysis. Infants with botulism appear lethargic, feed poorly, are constipated, and have a weak cry and poor muscle tone. Throughout all such symptoms, the victims are fully alert, and the results of sensory examination are normal.
In foodborne botulism cases, symptoms usually begin anywhere between 12 and 72 hours after the ingestion of toxin-containing food. Longer incubation periods—up to 10 days—are not unknown, however. The duration of the illness is from 1 to 10 (or more) days, depending on host-resistance, the amount of toxin ingested, and other factors. Full recovery often takes from weeks to months. If diagnosed early, foodborne botulism can be treated with an antitoxin that blocks the action of toxin circulating in the blood. This can prevent patients from worsening, but recovery still takes many weeks. The mainstay of therapy is supportive treatment in intensive care, and mechanical ventilation in case of respiratory failure, which is common.