Fundamental Food Microbiology, Third Edition - Fuad Fathir

FOODBORNE INTOXICATIONS 351
toxins, only a very small amount (1 ng/kg body weight) is necessary for severe
symptoms and even death. In general, neurological symptoms include blurred or
double vision; difficulty in swallowing, breathing, and speaking; dryness of the
mouth; and paralysis of different involuntary muscles, which spreads to the diaphragm,
lungs, and heart. Death usually results from respiratory failure.
The toxins are antigenic; thus antitoxins are available. Soon after the onset of
the symptoms and if the amount of toxin consumed is fairly low, trivalent antitoxins
(against botulin A, B, and E) can be administered to treat the disease. But in some
advanced cases, especially if the diagnosis is delayed, antitoxin administration may
not be successful. In the U.S., even with available facilities, botulism accounts for
ca. 19% of the total foodborne fatal cases. 10–12
E. Food Association
The events in a foodborne botulism involve contamination of a food with Clo.
botulinum spores, survival of the spores during processing, and the ability of the
spores to germinate and outgrow and the cells to multiply when the product is abused
(temperature and time). The largest number of outbreaks are associated with fruits
and vegetables (Table 24.2), 1 mainly low-acid vegetables (e.g., green beans, corn,
spinach, asparagus, pepper, and mushrooms) and fruits (e.g., figs and peaches). The
next highest incidence was with finfish, which includes fermented, improperly
cooked, and smoked fish and fish eggs. Type E was associated predominantly with
fish and Types A and B were associated with vegetables. The major cause of
outbreaks was improper home canning of the contaminated products. Between 1983
and 1987, of the 231 botulism outbreaks in the U.S., 56 occurred at home. The
occurrence of botulism from meat, poultry, and dairy products is low, probably
because they are mostly heated and eaten quickly. Several outbreaks from unlikely
foods (sautéed onions or baked potatoes) have been recorded, but in many instances
the foods were subjected to temperature abuse (held for a long time at warm
temperature). Some condiments, such as chili peppers, relish, and sauce, have also
been associated with outbreaks.
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Table 24.2 Food Types Involved in Confirmed Botulism Outbreaks from 1973 to 1987
in the U.S.
Food Types No. % Food Types No. %
Beef stew 2 0.9 Mushrooms 5 2.2
Chicken 1 0.4 Beverages
(nondairy)
5 2.2
Dairy
products
1 0.4 Pork 1 0.4
Finfish 35 15.2 Turkey 1 0.4
Fruits and
vegetables
99 42.9 Othera 40 17.3
Mexican food 3 1.3 Unknown 38 16.4
a Not identified, but probably include several types of food, many of which were of unlikely
categories, and no single type was involved in a large number of outbreaks.