492 Chapter 28
food item in Japan called Natto, in which the
organisms produce polymer of glutamic
acids as well as other fl avor compounds.
Control of Bacillus food poisoning is
complicated by the ubiquitous nature of this
organism. The best measures are to prevent
the spore from germinating and to prevent
multiplication of vegetative cells in cooked
and ready - to - eat foods. Freshly cooked food
eaten hot immediately after cooking should
not be a problem. However, slow reheating
of previously cooked rice products should be
treated with caution. Refrigeration of leftover
cooked rice products is highly recommended
as a preventive measure.Campylobacter jejuni
Campylobacter jejuni , recognized as an
emerging pathogen in the past 10 years, has
been reported as the most common bacterial
cause of gastrointestinal infection in humans,
even surpassing rates of illness caused by
Salmonella and Shigell a. In 1992 in the
United States, there were 6 outbreaks, 138
cases, and 2 deaths reported. In 2002, there
were 25 outbreaks, 539 cases and 1 death.
Campylobacter was originally called Vibrio
fetus , because it was fi rst recognized as an
agent of infertility and abortion in sheep and
cattle. The organism is a member of the
family Spirillaceae because of the physio-
logic and morphologic similarities to
Spirillum.
The organism is a Gram - negative, slender,
curved bacteria that is motile with a single
polar fl agellum. It neither ferments nor oxi-
dizes carbohydrates, is oxidase positive,
reduces nitrates but will not hydrolyze gelatin
or urea, and is methyl red and Voges -
Proskauer reaction negative. It will grow
between 25 ° and 43 ° C. The organism is an
obligate microaerophile that grows optimally
in 5% oxygen. This attribute has been used
for isolation of the organism by applying
appropriate gas mixtures into the head space
of cultivation media. Recently in the author ’ sborne illness for a long time. In 1991 in the
United States, there were 5 outbreaks, 253
cases, and no deaths reported. In 2002, there
were 14 outbreaks, 691 cases, and no deaths.
These are Gram - positive, aerobic, spore -
forming rods occurring widely in nature and
contaminating foods easily. Because of the
general resistance of this organism ’ s spores
and the prolifi c biochemical activity of the
vegetative cells, it can be considered one of
the most important environmental bacterial
contaminants of foods. Two distinct clinical
symptoms are caused by this organism. The
diarrheal syndrome occurs 12 to 24 hours
after ingestion of large numbers (about 1
million) of viable B. cereus and includes
abdominal pain, watery diarrhea, rectal
tenesmus, and nausea without vomiting. The
diarrheal enterotoxin is formed in the intes-
tine of the host and causes the disease. The
diarrheal syndrome is the result of consum-
ing proteinaceous foods, such as pudding,
milk and milk products, sauces, and vegeta-
bles. The emetic syndrome causes illness
almost exclusively associated with cooked
rice and noodles and is characterized by a
rapid onset (1 – 5 h) with nausea, uncontrol-
lable vomiting, and malaise. The toxin is
preformed in the food by large numbers of B.
cereus (1 to 10 million cells). Large numbers
of viable B. cereus found in food indicates
poor food handling and storage practices. To
truly assess the food - borne illness potential,
the toxins involved must be detected.
Currently, no diagnostic kits are available for
the detection of emetic toxin, but there are
two kits available for diarrheal enterotoxin,
one by OXOID, utilizing reverse passive
latex agglutination tests, and another by
Tecra, utilizing the ELISA format.
Other Bacillus suspected of causing food -
borne diseases include Bacillus licheniformis
and Bacillus subtilis , in which large numbers
(10^5 to 10^6 organisms/gram of food) of these
organisms are ingested by susceptible
persons. It should be noted that Bacillus sub-
tilis var natto is used to ferment a popular