Notes About Bacillus cereus food
poisoning with foodborne toxins :
What is Bacillus cereus?
Bacillus cereus is a pathogenic food-borne illness-causing organism that is widely
distributed in nature such as on plants, soils, and GI tracts of insects and mammals.
They are also present in food production plants and are capable of
contaminating a large number of raw materials and food products due to their
resistant endospores that can survive in harsh conditions.
Bacillus cereus is a causative pathogenic organism that causes two types of
food poisoning disease: the diarrheal type and the emetic type.
Bacillus cereus produces a complex enterotoxin in the small intestine which
causes a diarrheal type of food poisoning and the consumption of food with the
presence of heat-stable toxins causes an emetic type of food poisoning.
It causes opportunistic infections such as bacteremia, septicemia, pneumonia,
meningitis, gastritis, liver failure, liver necrosis and brain edema.
Other species belonging to Bacillus that are responsible for causing food-borne
illness are B. subtilis, B. licheniformis, B. pumilus, B. weihenstephanensis, B.
anthracis, B. mycoid, B. pseudomycoides and B. thuringiensis.
Biological characteristics of Bacillus
cereus
Gram-positive bacteria
Spore-former
Aerobic-to-facultative
Motile
, Rod-shaped bacilli
Grow on temperature range (8 – 55°C)
Optimum temperature – 25 to 37°C
pH range (4.9 – 9.3)
Salt concentration up to 7.5%
Endospores are resistant to high heat, radiation, desiccation and
disinfectants.
Sources of contamination
Due to the heat-resistant spore of B. cereus, it is capable of
contaminating the whole food processing units from the raw
materials to packaging and storage.
The biotechnological equipment and machines are also
contaminated.
The organism is inhabitat to soil and is transmitted to the
vegetables and crops easily.
Food products such as rice, wheat, pasta, flour, dairy products,
meat products, spices, infant foods, fish, soups, vegetables and
fruits are frequently contaminated.
B. thuringiensis used as a biopesticide produces enterotoxins when
spread on plants and vegetation affects the health of a consumer.
Many outbreaks have been reported in the case of food consumed
by B. cereus contamination.
Bacillus cereus foodborne toxins
Bacillus cereus produces protein toxins namely diarrheal toxin and
emetic toxin.
Diarrheal toxin:
A diarrheal toxin is formed when vegetative cells containing foods
are consumed and it starts to grow in the small intestine.
Diarrheal toxins are proteases sensitive such as pronase, pepsin,
trypsin and chymotrypsin.
The total infectious dose capable of causing diarrheal illness is
about 104 to 109 cfu/gm.
The incubation period starts from 8 to 16 hours of ingestion and
lasts only for 24 to 48 hours.
poisoning with foodborne toxins :
What is Bacillus cereus?
Bacillus cereus is a pathogenic food-borne illness-causing organism that is widely
distributed in nature such as on plants, soils, and GI tracts of insects and mammals.
They are also present in food production plants and are capable of
contaminating a large number of raw materials and food products due to their
resistant endospores that can survive in harsh conditions.
Bacillus cereus is a causative pathogenic organism that causes two types of
food poisoning disease: the diarrheal type and the emetic type.
Bacillus cereus produces a complex enterotoxin in the small intestine which
causes a diarrheal type of food poisoning and the consumption of food with the
presence of heat-stable toxins causes an emetic type of food poisoning.
It causes opportunistic infections such as bacteremia, septicemia, pneumonia,
meningitis, gastritis, liver failure, liver necrosis and brain edema.
Other species belonging to Bacillus that are responsible for causing food-borne
illness are B. subtilis, B. licheniformis, B. pumilus, B. weihenstephanensis, B.
anthracis, B. mycoid, B. pseudomycoides and B. thuringiensis.
Biological characteristics of Bacillus
cereus
Gram-positive bacteria
Spore-former
Aerobic-to-facultative
Motile
, Rod-shaped bacilli
Grow on temperature range (8 – 55°C)
Optimum temperature – 25 to 37°C
pH range (4.9 – 9.3)
Salt concentration up to 7.5%
Endospores are resistant to high heat, radiation, desiccation and
disinfectants.
Sources of contamination
Due to the heat-resistant spore of B. cereus, it is capable of
contaminating the whole food processing units from the raw
materials to packaging and storage.
The biotechnological equipment and machines are also
contaminated.
The organism is inhabitat to soil and is transmitted to the
vegetables and crops easily.
Food products such as rice, wheat, pasta, flour, dairy products,
meat products, spices, infant foods, fish, soups, vegetables and
fruits are frequently contaminated.
B. thuringiensis used as a biopesticide produces enterotoxins when
spread on plants and vegetation affects the health of a consumer.
Many outbreaks have been reported in the case of food consumed
by B. cereus contamination.
Bacillus cereus foodborne toxins
Bacillus cereus produces protein toxins namely diarrheal toxin and
emetic toxin.
Diarrheal toxin:
A diarrheal toxin is formed when vegetative cells containing foods
are consumed and it starts to grow in the small intestine.
Diarrheal toxins are proteases sensitive such as pronase, pepsin,
trypsin and chymotrypsin.
The total infectious dose capable of causing diarrheal illness is
about 104 to 109 cfu/gm.
The incubation period starts from 8 to 16 hours of ingestion and
lasts only for 24 to 48 hours.
