Fundamental Food Microbiology, Third Edition - Fuad Fathir

OPPORTUNISTIC PATHOGENS, PARASITES, AND ALGAL TOXINS 409
Spoilage of some refrigerated foods has been recognized, such as pasteurized
milk, due to growth of several Bacillus spp. The psychrotrophic Bacillus spp. isolated
in one study includes strains of Bacillus cereus, Bac. mycoides, Bac. circulans, Bac.
lentus, Bac. polymyxa, and Bac. pumilus. In this study, an isolate was considered a
psychrotroph if it grew at £6�C. Many isolates of these species produced toxins.
However, the capability of these toxins to cause gastroenteritis was not examined.
This aspect may need further consideration as more and more low-heat-processed
foods are stored at refrigeration temperature for long times. 6
Some mesophilic Bacillus species, such as several Bac. licheniformis strains, are
toxigenic and are suspected to have the potential to cause foodborne disease, especially
in foods stored or temperature abused at �10�C. 7
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III. BIOGENIC AMINES
Different types of amines can form in many protein-rich foods by the decarboxylation
of amino acids by the specific amino acid decarboxylases of microorganisms. 8–10
Some of these amines are biologically active and cause illness when consumed in
considerable amounts. Examples of biogenic amines are histamine (produced from
L-histidine) and tyramine (produced from L-tyrosine). Many bacteria found in foods
can produce very active histidine or tyrosine decarboxylases, and, if free L-histidine
and L-tyrosine are present, can convert them to histamine and tyramine, respectively.
Some food spoilage bacteria and even several lactobacilli can have very active
histidine and tyrosine decarboxylases. The protein-rich foods associated with biogenic
amine poisoning include cheeses ripened for a long time, mold-ripened
cheeses, fermented sausages stored for a long time, and different types of fish.
Histamine poisoning of fish origin is further discussed here. 8–10
A. Histamine (Scombroid) Poisoning
Histamine poisoning is called scombroid poisoning, as the disease was initially
recognized to occur from the ingestion of spoiled fishes of scombroid groups (tuna,
mackerel, and bonito). 9 However, it is now recognized that the illness can occur
from the consumption of other types of spoiled fish, such as mahi mahi, bluefish,
yellowtail, amberjack, herring, sardines, and anchovies. Most of these fish have a
high level of free L-histamine in their tissues. In addition, the breakdown of muscles
by autolytic proteases and bacterial proteases produced during their growth in fish
release L-histidine. Histidine decarboxylase produced by bacteria growing in fish
catalyzes L-histidine to histamine. The most important bacterial species associated
with histamine production in fish is Morganella morganii. Several other species are
also found, namely, Kle. pneumoniae, Proteus spp., Ent. aerogenes, Hafnia alvei,
and Vibrio algenolyticus. In fermented fish products, several Lactobacillus spp. have
also been implicated in histamine production. 9
The symptoms of histamine poisoning include gastrointestinal (GI) (nausea,
vomiting, abdominal cramps, and diarrhea), neurological (tingling, flushing, palpitations,
headache, burning, and itching), cutaneous (hives, rash), and hypotension.
Generally, high levels of histamine in fish are necessary to produce the symptoms.