Botulinum toxin
In 1895 (seventy-five years later), Émile van Ermengem, professor of bacteriology and a student of Robert Koch, correctly described "Clostridium botulinum" as the bacterial source of the toxin. Thirty-four attendees at a funeral were poisoned by eating partially salted ham, an extract of which was found to cause botulism-like paralysis in laboratory animals. Van Ermengem isolated and grew the bacterium, and described its toxin, which was later purified by P Tessmer Snipe and Hermann Sommer.
Canning
Foodborne botulism results from contaminated foodstuffs in which "C. botulinum" spores have been allowed to germinate and produce botulism toxin, and this typically occurs in canned non-acidic food substances that have not received a strong enough thermal heat treatment. "C. botulinum" prefers low oxygen environments and is a poor competitor to other bacteria, but its spores are resistant to thermal treatments. When a canned food is sterilized insufficiently, most other bacteria besides the "C. botulinum" spores are killed, and the spores can germinate and produce botulism toxin. Botulism is a rare but serious paralytic illness, leading to paralysis that typically starts with the muscles of the face and then spreads towards the limbs. The botulinum toxin is extremely dangerous because it cannot be detected by sight or smell, and ingestion of even a small amount of the toxin can be deadly. In severe forms, it leads to paralysis of the breathing muscles and causes respiratory failure. In view of this life-threatening complication, all suspected cases of botulism are treated as medical emergencies, and public health officials are usually involved to prevent further cases from the same source.