Fundamental Food Microbiology, Third Edition - Fuad Fathir

392 FUNDAMENTAL FOOD MICROBIOLOGY
H. Detection Method .............................................................................400
I. Analysis of an Outbreak ..................................................................400
V. Escherichia coli Gastroenteritis ...............................................................401
A. Importance ........................................................................................401
B. Characteristics ..................................................................................401
C. Habitat ..............................................................................................402
D. Toxins and Toxin Production ...........................................................402
E. Disease and Symptoms ....................................................................402
F. Food Association ..............................................................................402
G. Prevention .........................................................................................403
H. Detection Methods ...........................................................................403
VI. Conclusion ................................................................................................403
References ............................................................................................................403
Questions ..............................................................................................................404
I. INTRODUCTION
The pathogenesis and disease symptoms of several pathogens associated with foodborne
and waterborne gastroenteritis are somewhat different from classical food
poisoning or foodborne infection caused by the pathogens described in Chapter 24
and Chapter 25. Although the differences are not always very clear, in this chapter
the gastroenteritis caused by Clostridium perfringens, Bacillus cereus, Vibrio cholerae,
and enteropathogenic Escherichia coli is described as toxicoinfection. The first
two are Gram-positive sporeformers, and the last two are Gram-negative small rods.
For each pathogen, importance, characteristics, nature of toxins, food association,
and control measures are discussed. For some, detection methods and analysis of
outbreaks are also included.
The following are some characteristics of foodborne toxicoinfection:
1. For sporeformers, ingestion of large numbers of live vegetative cells is usually
necessary.
2. Vegetative cells of sporeformers do not multiply in the digestive tract, but sporulate
and release toxins.
3. For Gram-negative bacteria, live cells can be ingested in moderate numbers.
4. Gram-negative cells rapidly multiply in the digestive tract.
5. Many cells also die, releasing toxins.
6. Toxins of both groups produce the gastroenteritis symptoms.
A. Importance
II. CLOSTRIDIUM PERFRINGENS GASTROENTERITIS
Gastroenteritis caused by Clo. perfringens has several specific characteristics. In
most outbreaks, large numbers of cases are involved. In the U.S. in the 1960s and