334 ◾ Fundamental Food Microbiology
Analysis of a Foodborne Botulism Case
On May 4, 1992, in New Jersey, a man of Egyptian origin developed dizziness, facial drooping,
dry mouth, weakness, and respiratory difficulties. Within two days, two more family members
developed similar symptoms. The cases were diagnosed as botulism and treated with trivalent (A,
B, E) botulinal antitoxins. The source of the toxin was traced to an ethnic fish preparation made
with uneviscerated, salt-cured fish. On May 3, the family obtained the product from outside and
consumed it without cooking.
The sequence of events was most probably as follows: The fish had Clo. botulinum spores in
the gut (probably type E) from the water and water sediment. The uneviscerated fish were cured
in salt, the concentration of which was not high enough to prevent germination, cell growth, and
toxin production. The product was consumed, probably in different amounts, without cooking by
the family members, who developed symptoms at different times. The outbreak could have been
avoided by removing the viscera, curing the fish in recommended salt concentrations, and heating
prior to eating.
Conclusion
Foodborne pathogenic microorganisms producing toxins while growing in foods and food ingredients are involved in human foodborne intoxication. The toxins can be proteins or small organic
molecules and heat labile or heat stable. A toxin, depending upon the pathogen, can produce only
enteric symptoms or neurological symptoms or cancer. The incidence of foodborne intoxication
can be reduced by using proper sanitation and preservation of foods during processing and subsequent handling.
QUESTIONS
1. List five characteristics of foodborne intoxication.
2. Describe some growth characteristics of Staphylococcus aureus strains that give them an
advantage for growth and toxin production in a food. Name two known food types that
have the highest incidence of staphylococcal poisoning and state the predisposing causes.
3. List the characteristics of the enterotoxins of Sta. aureus and discuss the mechanisms by
which they produce enteric symptoms.
4. List the symptoms of staphylococcal food poisoning and discuss how the disease can be differentiated from other food poisoning diseases of microbial origin.
5. From a case of a staphylococcal food poisoning outbreak (get it from the instructor or the
Internet), determine the sequence of events in the outbreak. What precautions could have
been taken to avoid the incidence?
6. Describe how foodborne botulism differs from infant botulism.
7. List the types of Clostridium botulinum associated with food intoxication and describe the
changes that can occur from their growth in a food high in protein and a food low in protein.
8. List the toxins associated with foodborne botulism in humans and describe the mechanisms
by which the toxins produce neurological symptoms.
9. Discuss how a combination of several environmental parameters can be used to control
growth of Clostridium botulinum in a food.
10. List two food groups frequently associated with botulism in the United States. Suggest four
methods that could reduce the incidence.
Analysis of a Foodborne Botulism Case
On May 4, 1992, in New Jersey, a man of Egyptian origin developed dizziness, facial drooping,
dry mouth, weakness, and respiratory difficulties. Within two days, two more family members
developed similar symptoms. The cases were diagnosed as botulism and treated with trivalent (A,
B, E) botulinal antitoxins. The source of the toxin was traced to an ethnic fish preparation made
with uneviscerated, salt-cured fish. On May 3, the family obtained the product from outside and
consumed it without cooking.
The sequence of events was most probably as follows: The fish had Clo. botulinum spores in
the gut (probably type E) from the water and water sediment. The uneviscerated fish were cured
in salt, the concentration of which was not high enough to prevent germination, cell growth, and
toxin production. The product was consumed, probably in different amounts, without cooking by
the family members, who developed symptoms at different times. The outbreak could have been
avoided by removing the viscera, curing the fish in recommended salt concentrations, and heating
prior to eating.
Conclusion
Foodborne pathogenic microorganisms producing toxins while growing in foods and food ingredients are involved in human foodborne intoxication. The toxins can be proteins or small organic
molecules and heat labile or heat stable. A toxin, depending upon the pathogen, can produce only
enteric symptoms or neurological symptoms or cancer. The incidence of foodborne intoxication
can be reduced by using proper sanitation and preservation of foods during processing and subsequent handling.
QUESTIONS
1. List five characteristics of foodborne intoxication.
2. Describe some growth characteristics of Staphylococcus aureus strains that give them an
advantage for growth and toxin production in a food. Name two known food types that
have the highest incidence of staphylococcal poisoning and state the predisposing causes.
3. List the characteristics of the enterotoxins of Sta. aureus and discuss the mechanisms by
which they produce enteric symptoms.
4. List the symptoms of staphylococcal food poisoning and discuss how the disease can be differentiated from other food poisoning diseases of microbial origin.
5. From a case of a staphylococcal food poisoning outbreak (get it from the instructor or the
Internet), determine the sequence of events in the outbreak. What precautions could have
been taken to avoid the incidence?
6. Describe how foodborne botulism differs from infant botulism.
7. List the types of Clostridium botulinum associated with food intoxication and describe the
changes that can occur from their growth in a food high in protein and a food low in protein.
8. List the toxins associated with foodborne botulism in humans and describe the mechanisms
by which the toxins produce neurological symptoms.
9. Discuss how a combination of several environmental parameters can be used to control
growth of Clostridium botulinum in a food.
10. List two food groups frequently associated with botulism in the United States. Suggest four
methods that could reduce the incidence.