Fundamental Food Microbiology, Third Edition - Fuad Fathir

IMPORTANT FACTS IN FOODBORNE DISEASES 329
1. Intoxication
Illness occurs as a consequence of ingesting a preformed bacterial or mold toxin
because of its growth in a food. A toxin has to be present in the contaminated food.
Once the microorganisms have grown and produced toxin in a food, there is no need
of viable cells during consumption of the food for illness to occur. Staph food
poisoning is an example.
2. Infection
Illness occurs as a result of the consumption of food and water contaminated with
enteropathogenic bacteria or viruses. It is necessary that the cells of enteropathogenic
bacteria and viruses remain alive in the food or water during consumption. Viable
cells, even if present in small numbers, have the potential to establish and multiply
in the digestive tract to cause the illness. Salmonellosis and hepatitis A are examples.
3. Toxicoinfection
Illness occurs from ingesting a large number of viable cells of some pathogenic
bacteria through contaminated food and water. Generally, the bacterial cells either
sporulate or die and release toxins to produce the symptoms. Clo. perfringens
gastroenteritis is an example.
In addition to the pathogenic microorganisms associated with foodborne illnesses,
some bacterial species and strains normally considered nonpathogenic can
cause gastroenteritis, especially in susceptible individuals. They are designated as
opportunistic pathogens. They are normally required to be alive and present in large
numbers when consumed through a contaminated food.
G. Predominant Bacterial and Viral Pathogens Associated with
Foodborne Diseases
Although many pathogenic bacterial species and viruses have been implicated with
foodborne (and waterborne) disease outbreaks, some have occurred at a higher
frequency than others (Table 23.4). Of the two most common pathogens associated
with foodborne intoxication from 1983 to 1987, the number of deaths was higher
for Clo. botulinum, but the total number of cases was much higher for Sta. aureus.
Among the enteric pathogens, the largest number of outbreaks, cases, and fatalities
resulted from foodborne infections caused by Salmonella. Toxicoinfection outbreaks
and number of cases were higher for Clo. perfringens than for Bacillus cereus. Of
the two most common viral diseases from contaminated food and water, the number
of outbreaks was higher for hepatitis A, but Norwalk-like viruses affected more
people. From 1983 to 1987, salmonellosis was associated with the highest number
of outbreaks of all foodborne diseases, affecting the largest number of individuals
and causing the most deaths. In contrast, botulism affected the least number of people
but caused the highest number of deaths in the affected people (17 out of 140). No
death was reported from staphylococcal intoxication, Bac. cereus gastroenteritis, or
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