BIO101 Lecture Notes - Lecture 2: Foodborne Illness, Botulism, Clostridium
11 Jan 2022
Department
Course
Professor
Notes About Botulism Food Poisoning by
Clostridium botulinum :
What is Botulism Food Poisoning?
Botulism is a life-threatening food-borne disease that causes neuroparalysis from
the consumption of botulinum neurotoxins (BoNTs). Botulism is a rare disease
but has a high fatality rate even a small amount of toxin can kill millions.
• Clostridium botulinum causes intoxication i.e, disease occurs either from
ingesting preformed BoNTs in foods or production of BoNTs in the intestine.
• There are seven distinct botulinum toxins (Type A to G) that cause disease in
humans and animals.
• The clinical-epidemiological forms of botulism are food-borne botulism,
infant botulism and wound botulism.
• Botulinum toxins Type A, B and E are associated with food-borne botulism in
humans.
• The lethal dose of BoNTs for humans is 0.2µg to 2µg per kg body weight.
• Botulinum toxin is considered a hazardous biological substance in the
environment.
Source of Clostridium botulinum contamination
• C. botulinum is anaerobic, spore former, gram-positive bacterium and its
spores are widely distributed in the environment from the soil to sewage,
mud, lakes, sediments of sea and oceans and are also found in the intestine of
land and aquatic animals.
• Due to the nature of the bacterium to grow in wide distribution, its spore can
contaminate foods where it colonizes and produces toxins.
• C. botulinum spores contaminating honey and syrup which are the major
source of infant botulism.
• Poorly processed canned foods are also the main source of contamination as
the spores can tolerate high heating temperatures during processing.
• Other food sources include various types of lake and sea fishes, smoked, salt-
dried and fermented meat products.
• Type A and B BoTNs are also commonly present in soil and biofertilizers,
therefore, they are likely to contaminate vegetables and fruits.
• Improperly cooked vegetable products such as beans, baked potatoes, corn,
celery, mushrooms, onions and olives.
Clostridium botulinum neurotoxin production
• The BoNTs are extracellular proteins produced by C. botulinum that weighs
around 150kDa.
• Based on the physiology and phylogenetic of bacteria, BoNTs have seven
distinct serotypes from Type A to H.
• All seven toxins are categorized into four groups based on proteolytic and
non-proteolytic activity: Group I, II, III and IV.
• Group I proteolytic Type A, B and F can proliferate on temperature range
from 10 to 20°C similarly Group II non-proteolytic Type B, E and F at 2.5 to
3°C.
• Group III includes non-proteolytic Type C and D while Group IV has Type G.
Document Summary
Botulism is a life-threatening food-borne disease that causes neuroparalysis from the consumption of botulinum neurotoxins (bonts). Improperly cooked vegetable products such as beans, baked potatoes, corn, celery, mushrooms, onions and olives. In infant botulism, babies under 1 year are mostly affected being a poorly developed gut microflora where the toxins are formed in the intestine. In infants, symptoms like a weak hoarse cry, ptosis, poor suck, inability to hold the head upright and weak muscles may appear. Epidemiology of botulism food poisoning: botulinum toxin was used as a biological agent during world war ii by the. British, american and japanese military: the large outbreak till reported was in egypt in 1991 by the consumption of. Later, both were hospitalized suffering from respiratory failure and were on ventilation for several months: about 90% of the botulinum cases occur in the united states reporting 9 to.
