Clostridium botulinum food poisoning

In life, we only know that food can be poisonous if it is not cooked properly, and that mushrooms can be poisoned if eaten improperly. However, we do not realize that many things can be poisonous and are closely related to our bodies, such as Clostridium botulinum food poisoning. This type of food poisoning requires careful understanding. What factors cause people to be poisoned, and under what circumstances will the poisoning occur?

pathogen

Clostridium botulinum (C. botulinum) food poisoning is caused by the exotoxin produced by Clostridium botulinum, namely botulinum toxin.

The pathogen Clostridium botulinum is a Gram-positive, anaerobic, short and thick rod that forms oval spores that are thicker than the bacterial body at 20-25℃. When the pH is lower than 4.5 or greater than 9.0, or when the ambient temperature is lower than 15. C or above 55 ℃, Clostridium botulinum spores cannot reproduce and do not produce toxins. Clostridium botulinum spores are highly resistant and need to be subjected to high-pressure steam 121. C for 30 minutes, or dry heat at 180℃ for 5 to 15 minutes, or wet heat at 100℃ for 5 hours to kill it.

Botulinum toxin is a strong neurotoxin that is 10,000 times more toxic than potassium cyanide. The lethal dose for humans is about 0.1 g. Depending on the antigenicity of the toxins produced, botulinum toxin is divided into 8 types: A, B, Ca, CB, D, E, F, and G. Four types, A, B, E, and F, cause human poisoning. Among them, types A and B are the most common. Most of the botulism poisoning reported in my country is type A, followed by types B and E.

Unlike the typical exotoxin production method of other bacteria, botulinum toxin is not released by living bacteria, but first produces a non-toxic toxin precursor in the cytoplasm of living Clostridium botulinum. This precursor is a complex composed of a neurotoxin subunit and one or more non-toxin subunits. When the bacteria die and autolyze, the complex toxin precursor is released. This precursor is heat unstable and is destroyed by heating at 75-850°C for 5-15 minutes, or at 100°C for 1 minute. The complex form of botulinum toxin enters the stomach with food and can resist the digestion of gastric acid and enzymes. It enters the small intestine and is decomposed by small intestinal trypsin.

Unlike the typical exotoxin production method of other bacteria, botulinum toxin is not released by living bacteria, but first produces a non-toxic toxin precursor in the cytoplasm of living Clostridium botulinum. This precursor is a complex composed of a neurotoxin subunit and one or more non-toxin subunits.

When the bacteria die and autolyze, the complex toxin precursor is released. This precursor is heat unstable and is destroyed by heating at 75-85°C for 5-15 minutes, or at 100°C for 1 minute. The complex form of botulinum toxin enters the stomach with food and can resist the digestive effects of gastric acid and enzymes. It enters the small intestine, is broken down by small intestinal trypsin, and dissociates into neurotoxins in a higher pH environment, which are absorbed into the blood in the small intestine.