Food Biochemistry and Food Processing

696 Part VII: Food Safety

result in a high morbidity and mortality rate. For
example, complications such as hemolytic uremic
syndrome can result in kidney failure and death
(Riley et al. 1983, Karmali 1989). Sources of bacte-
rial infections are not limited to contaminated foods;
contaminated water and person-to-person transmis-
sion have also been implicated. For example, in a
waterborne outbreak of E. coli0157:H7 in Walker-
ton, Ontario, 1700 cases and seven deaths were
reported. This led to changes in the Ontario Drink-
ing Water Regulations to include strict water treat-
ment procedures and zero tolerance for the presence
of coliforms and E. coliin drinking water. Current
food safety programs in the food industry must now
document the use of pathogen-free water in food
production and processing facilities.

CAMPYLOBACTERENTERITIS

Campylobacter jejuniand C. coliare the species of
Campylobacterimplicated in most Campylobacter
enteritis infections. Other species of Campylobacter
such as C. lariand C. upsaleusismay also cause
Campylobacterenteritis. Symptoms of Campylob-
acterinfection in humans are watery and/or bloody
diarrhea, abdominal pain, fever, and general mal-
aise. The disease is usually self-limiting, and antibi-
otics are required only when complications occur. It
is estimated that Campylobacterenteritis accounts
for 10% of cases of foodborne illness, and death is
rarely reported. Most cases of this disease are spo-
radic, and foods of animal origin, particularly poul-
try, are largely responsible for most infections.
Contaminated fruits and vegetables have also been
implicated in Campylobacterenteritis cases.

SALMONELLOSIS

Salmonellosis infection ranks second in incidence to

Campylobacterenteritis. This organism is ubiqui-

tous (present everywhere) in the environment, espe-

cially in the feces of most food-producing animals;

hence, a variety of foods are readily contaminated

by this organism. Salmonellaare present in animals

without causing apparent illness. However, certain

serotypes of Salmonellasuch as S. enteritidis, can

penetrate poultry reproductive organs, resulting in

contamination of egg content and posing a health

risk to consumers. Salmonellosis symptoms include

watery diarrhea, abdominal pain, nausea, fever, head-

ache, and occasional constipation. Hospitalization

may be required in cases of severe infections. Foods

that can become contaminated with Salmonellain-

clude meat, raw milk, poultry, eggs, dairy products,

and other types of foods that can become contami-

nated with fecal material. An increase in the number

of cases of Salmonellosis linked to consumption of

contaminated fruits and vegetables such as bean

sprouts, raw tomatoes, melons, and cantaloupes has

been reported. In addition to fecal contamination,

cross-contamination of foods by Salmonelladuring

food preparation can be a source of foodborne illness.

LISTERIOSIS

Listeriosis is caused by Listeria monocytogenes.

The ubiquitous nature of this organism contributes

to the widespread incidence of the organism in

foods. It is psychrotropic in nature and is able to

grow at refrigeration temperatures. Hence, this or-

ganism is of concern in refrigerated foods with ex-

Table 30.2.The Incidence of the Four Most Frequent Foodborne Disease–Causing Pathogens
in Canada and the United States

Estimated Cases/Year (Based on Population Ratio)

Bacteria Canada United Statesa

Campylobacter 110,000–700,000 1,100,000–7,000,000
Listeria 93–177 928–1,767
Salmonella 69,600–384,000 696,000–3,840,000
Verotoxigenic E. coli 1,600–3,200 16,000–32,000
(Including E.coliO157:H7)

Total 181,3000–1,087,400 1,812,900–10,873,800
aAdapted from Buzby and Roberts 1997.