RAI BugWiki

Clostridium botulinum

[notice]Hazard Group 2 | Toxigenic | Notifiable to Local Authority[/notice]

[pullquote align=”left|center|right” textalign=”left|center|right” width=”30%”]Produces a potent nerve toxin which vain twats inject into their faces. Ick. [/pullquote]Rare but deadly if not treated. Its toxin (sold as Botox®) causes paralysis and is one of the most potent nerve toxins ever studied. Grows well in places with low oxygen, such as cans of food that became contaminated before being sealed. Minute amounts of toxin can cause paralysis and suffocation. With antitoxin and a ventilator the paralysis usually goes away within weeks – or in severe cases, months. Can also infect babies. Constipation is often the first sign then a dull face, weak sucking, weak cry, less movement, trouble swallowing, more drooling than usual, muscle weakness and breathing problems. Children under 1 year old should never be fed honey which has been linked to infant botulism (but not to adult botulism). Wound botulism more common – principally in IV drug abusers. Ick.

Clostridium botulinum is one of the most important pathogens associated with food. The organism forms spores that are resistant to many common food process controls. Botulinum neurotoxins (BoNT) produced by vegetative cells of this Gram positive, anaerobic bacterium are among the most potent biological neurotoxins known. And some silly twats inject into their faces – it’s marketed as Botox®.

Foodborne botulism is a very severe intoxication, historically caused by eating preserved low acid, low oxygen foods (e.g. canned vegetables, meat and fish) in which C. botulinum had grown and produced BoNT. Symptoms appear between 12 and 36 hours after consuming the contaminated food with early nausea, vomiting and diarrhoea followed by paralysis of the eyes, mouth, throat and, progressively, muscles. Infant botulism is an extremely rare toxico-infection that occurs when C. botulinum grows and produces toxins in the intestines of babies; symptoms appear in 3-30 days and include constipation, lethargy, floppiness and breathing difficulties. This is why babies under a year old must not be fed honey; it’s a reservoir for botulinum spores.

Not all C. botulinum cause illness in humans. Strains produce one of seven known types of BoNT (A to G). Only those producing types A, B, E and F (rarely) cause botulism in humans. Strains are also separated into two groups based on physiological differences: Group I (can produce A, B or F toxin) are proteolytic and cause food spoilage; Group II (can produce B, E or F toxin) are non-proteolytic and may be present in foods without obvious spoilage.

Foodborne and infant botulism caused by C. botulinum in Groups I and II; more common is wound botulism in IV drug users – but as most food businesses don’t sell black tar smack as a rule we’ll stick to the foodborne disease.

[important]Growth and Control[/important]

Normally grows in the absence of oxygen.

C. botulinum produces a fatal toxin. This toxin is reasonably heat-stable but is destroyed by heating at >80°C. While the toxin has legitimate medical uses is one of the most potent nerve toxins ever discovered yet is injected into the faces of the vain and stupid under the trade name Botox®. The medical term for such people is ‘morons’.

Like the other clostridia C. botulinum forms a spore which makes proper cooling and reheating very important. Outbreaks have been implicated in low acid canned foods such as garlic and oil preparations. In addition, outbreaks have been caused by foil wrapped baked potatoes improperly cooled and then used to make potato salads.

While botulism poisoning is very rare, the organism is common in the soil and can survive in the environment as a resistant spore which stays dormant until exposed to conditions that support growth.

There are three main types of botulism – food borne botulism, intestinal botulism (due to proliferation of the organism in the gut) and wound botulism. Wound botulism in intravenous drug users is the most common presentation. The most common food-related outbreaks of botulism are linked to incautious home preserving of foodstuffs but – rarely – other canned foods can be tainted with the bacteria. Symptoms often begin with blurred vision and difficulty in swallowing and speaking, but diarrhoea and vomiting can also occur.

Symptoms of food borne botulism usually turn up 18 to 36 hours after eating tainted food, but it can take up to 10 days for symptoms to occur. The disease can progress to paralysis. Most cases will recover, but the recovery period can be many months. The disease is fatal in 5-10% of cases; death is due to respiratory failure.

When caught early an anti-toxin is available to stop the spread of the bacteria and emetics are often used in an attempt to rid the body of tainted food particles. Those canning their own foods need to take special care with those that are low in acid. Botulism is prevented in commercially-canned food by cooking at 121°C (250°F) for 3 minutes thus killing the spores. Honey is the only known dietary reservoir of botulinum spores. This is the reason honey is not recommended for infants under 12 months.

The Clostridium botulinum organism is killed by quat-based sanitisers – any Chemex product carrying the ‘Bio-Tested’ mark. The spores are killed by heating or by oxidisers such as Antibak.