Biomedical Engineering Reference
In-Depth Information
O157:H7,
Listeria monocytogenes
,
Campylobacter
, staphylococcal enterotoxin B,
Clostridium
botulinum
toxin, and others are discussed in this review.
18.2
Foodborne Pathogens
Foodborne pathogens cause either food poisoning or foodborne infections due to con-
sumption of preformed toxins or viable microorganisms, respectively. Most infections are
life threatening to immunologically challenged individuals. Children, the elderly people,
persons with acquired immunodeficiency syndrome (AIDS), persons with organ trans-
plants, persons receiving chemotherapy to treat malignancy, and pregnant women are
susceptible to many of the foodborne pathogens. Foodborne pathogens may cause
gastroenteritis, fatal hemolytic uremic syndrome, abortion, meningitis, atherosclerosis,
and neurological malady. Centers for Disease Control and Prevention (CDC) estimates
that there are about 76,000,000 illnesses due to foodborne pathogens, 325,000 hospital-
izations and 5,000 deaths each year in the United States (1). Economic losses for food-
borne diseases are estimated to be 6.9 billion dollars per year, and the losses are due to
product recalls, medical intervention, loss of work hours, and death. In the recent years
the threat of food bioterrorism unfolds a new perspective to the control and management
of foodborne infections. The threat of intentional introduction of food pathogens into
products means that those products that would not naturally be associated with a par-
ticular pathogen may now need to be screened for several pathogens or toxins capable of
surviving in the product. A single event of food bioterrorism can have tremendous
impact on our economy and lifestyle, since food and water are the most crucial entities
for life support.
Foodborne pathogens comprise bacteria, viruses, protozoa, molds, and nematodes.
Among the bacterial pathogens, some produce potent exotoxins like botulinum toxin
produced by
C. botulinum
, staphylococcal enterotoxin (SE) by
Staphylococcus aureus
, epsilon
toxin by
Clostridium perfringens
, and diarrheagenic or emetic enterotoxins by
Bacillus cereus
.
Exogenous administration or production of toxin in nanogram quantities in the food could
lead to serious consequences. Alternatively, when viable pathogenic bacterial cells are
ingested, they can cause infection. Organisms belonging to this group are
L. monocytogenes
,
C. perfringens
,
E. coli, Salmonella enterica
,
Vibrio
,
Shigella
,
Campylobacter
, and
Yersinia
species. In addition, spores also could present serious problems with foodborne
infections. Spores are resistant to most food-processing treatments and heat may trigger
their germination into vegetative cells, which can then produce toxins. If spores are intro-
duced into food (naturally or intentionally), they can germinate in the intestine and initiate
infection. For example,
Bacillus anthracis
spores, if consumed with food, could germinate in
the gut into vegetative cells, which can pass through intestinal epithelial cell linings induc-
ing severe inflammation and gastroenteritis, referred to as intestinal anthrax.
B. anthracis
spores are most deadly when inhaled (causing inhalation anthrax). In contrast, cutaneous
anthrax occurs when spores lodge on the skin causing milder disease. Examples of viral
foodborne diseases are Norwalk and Hepatitis A. An infective protein like prion, a causative
agent for mad cow disease or bovine spongiform encephalopathy (BSE), can also be trans-
mitted through meat and cause fatal neurologic disease (variant Creutzfeldt-Jacob disease—
vCJD) in humans. Important foodborne protozoan diseases are caused by
Giardia lamblia
,
Entamoeba histolytica
,
Toxoplasma gondi
,
Cryptosporidium parvum
,
Cyclospora cayetanensis
, and
Isospora belli
. Mycotoxins produced by various mold species are also problematic when con-
tained in cereal foods and meats, since they are carcinogenic, heptotoxic, or nephrotoxic.
