Microbial Hazards in Foods: Food-Borne Infections and Intoxications 491affects the abdomen of the patient, whereas
Vibrio parahemolyticus infection affects the
stomach of the patient. Detection of the
organism is best achieved by good selective
medium such as BTB - salt - Teepol agar.
Infection by this organism is prevented by
cooking seafood adequately.Vibrio vulnifi cus
This organism can be considered an emerg-
ing pathogen. It causes more than 90% of all
seafood related deaths in the United States.
The organism is widespread in estuarine
environments and has been isolated from
waters around the world. Consumption of
raw oysters contaminated with this organism
may lead to septicemia and death. Also, the
organism may invade people ’ s wounds when
they wade or work in contaminated water.
The organism is a typical vibrio - shaped
organism and is classifi ed as biotype 1 and
biotype 2. The organism grows well in
common bacteriological agars such as
MacConkey agar and blood agar. The incu-
bation time of the illness is from 1 to 7 days.
The disease involves fever, chills, nausea and
to a lesser extend vomiting, abdominal pain,
and diarrhea. Development of secondary
lesions can be serious and may result in vas-
culitis and necrotizing fasciitis, necessitating
surgical removal of tissues or even limb
amputation. Since the organism is killed by
common cooking practices, the problem is
the consumption of raw seafood, especially
raw oysters. People with liver damage and
with immunocompromised conditions should
defi nitely avoid eating raw seafood. There
was one outbreak with two cases and one
death reported in the United States in 1990.
There was no report of an outbreak of this
organism in 2002.Bacillus cereus
Bacillus cereus and other Bacillus species
have been implicated in food - borne diseases
only in recent years, although these organ-
isms have been suspected as agents of food -Vibrio parahemolyticus
Vibrio parahemolyticus is an organism that
has caused many cases of food - borne disease
in Japan for many years. This is because citi-
zens in Japan like to consume raw or under-
cooked seafood that may be contaminated
with the organism, especially in the summer
months when the water is warm in the
Northern Hemisphere. Most of the original
reports and research work were in Japanese
and not readily understandable or available
to microbiologists in the West. U.S. scientists
started working on the organism in earnest
around 1969. In 1971, three outbreaks of this
organism occurred in the United States. Since
U.S. citizens do not regularly consume raw
seafood, the sources of the illness were prob-
ably re - contamination of cooked foods. In
1990, there were 4 outbreaks and 21 cases
reported. The fact that no outbreaks were
reported in 1988, 1989, 1991, and 1992 indi-
cates that this organism is not a source of
common food - borne infections in the United
States. In 2002, there were 5 outbreaks, 40
cases, and no deaths reported.
The organism is a Gram - negative, curved
rod and is halophilic (salt loving), growing
best in a 3% to 4% salt medium (but can grow
in 8% salt also). The growth temperature
range is 15 ° to 40 ° C, and pH range is 5 to
9.6. The organism is sensitive to strep-
tomycin, tetracycline, chloramphenicol, and
novobiocin, but resistant to polymyxin
and colistin. The Kanagawa - positive strains
hemolyze human blood. Environmental
strains are negative for this test. The organ-
ism is distributed in fi sh and shellfi sh from
seawater as well as from freshwater. Most of
the outbreaks are recorded in the summer
months when the water is warm in the
Northern Hemisphere. Symptoms of the
disease occur about 12 hours after ingestion
of a large number of viable cells (10^5 /g) and
include abdominal pain, diarrhea, vomiting,
mild chills, and headache. The symptoms are
similar to those of salmonellosis but more
severe. It has been noted that salmonellosis