Food Biochemistry and Food Processing (2 edition)

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794 Part 8: Food Safety and Food Allergens

Outbreaks of food and waterborne illness have been reported in

the United States and the United Kingdom (Craun 1990, Porter

et al. 1990). Infection with this parasite is associated with unsan-

itary conditions, and contaminated water is the most common

source of infection.

Foodborne Fungi

Fungi most commonly associated with foodborne intoxica-

tions arePenicillium, Aspergillus,andFusarium. The types of

foods that may contain mycotoxin contamination are listed in

Table 41.3. A foodborne fungi outbreak associated with con-

sumption of corn contaminated withAspergillus flavuswas re-

ported in India. The outbreak involved 1000 cases and 100 deaths

(Krishnamachari et al. 1975). Mold growth can occur in foods

stored under high temperature or humidity, resulting in the pro-

duction of mycotoxin, which can be harmful to humans.

Foodborne Virus Infection

Viruses from human fecal origin can result in illness if ingested

with food or water. Food or waterborne viruses commonly as-

sociated with human illness are listed in Table 41.3. Viral gas-

troenteritis is caused by Norwalk-like viruses and in some cases

by the calicivirus and astrovirus groups. The symptoms often

include acute but short self-limiting episode of diarrhea and

vomiting. The viruses can be transmitted from person to person

via contaminated utensils and foods. Foodborne viral hepatitis

in humans is caused by the hepatitis A or hepatitis E virus. The

onset of hepatitis may be preceded by anorexia, fever, fatigue,

nausea, and vomiting. Infected individuals shed the organism in

feces, which if allowed to contaminate food or water, can result

in person-to-person transmission (Caul 2000).

EMERGING PATHOGENS AND

FOOD SAFETY

Emerging infectious diseases have increased in the last two

decades and are likely to increase in the future. Hence, the

characteristics of the etiologic agents of these diseases must

be considered when designing control measures to ensure food

safety. There are two types of emergence: true emergence and

reemergence. A true emergence involves the occurrence of mi-

crobial agent not previously identified as a public health threat. A

reemergence involves the occurrence of a microbial agent caus-

ing disease in a new way not previously reported or the reemer-

gence of a human disease after a decline in incidence. Emergence

may be due to the introduction of a new agent, to recognition

of an existing disease that was not previously detected, or to

environmental pressures resulting in occurrence of a pathogen

that can cause human disease. For example, the occurrence of

enterohemorrhagicE. coliO157:H7 as a pathogen in 1982 is

believed to be due to introduction of a new agent. The organism

was involved in two outbreaks that year in the United States,

and these outbreaks were associated with consumption of un-

dercooked hamburgers from a fast-food restaurant chain. Several

countries worldwide have reported outbreaks of infection caused

Table 41.4.Emerging Pathogens and Suspected

Causes of Emergence

Pathogens Cause of Emergence

SalmonellaDT104 Resistance to antibiotics

E. coliO157:H7 Development of a new pathogen

Cyclospora cayetanensis Development of a new pathogen

Cryptosporidium parvum Development of a new watershed

areas

Hepatitis E virus Newly recognized

Norwalk Virus Increased recognition

AeromonasSpp. Immunosuppression and

improved detection

C. jejuni Increased recognition,

consumption of uncooked

poultry

L. monocytogenes Increased awareness

Helicobacter pylori Increased recognition

Vibrio vulnificus Increased recognition

by this organism. The appearance ofSalmonella typhimurium

phage type 104 is another example of a new agent. Increases

in the use of antibiotics in humans and animals may have pro-

vided the environmental pressures resulting in the occurrence

ofSalmonella typhimuriumphage type 104 with multiresistance

to five antibiotics: ampicillin, chloramphenicol, streptomycin,

sulphonamides, and tetracycline. This multiresistant character-

istic leaves little choice of antibiotics for treatment of disease

caused by this organism. The occurrence ofListeria monocyto-

genesas a foodborne agent is an example of reemergence. The

organism is a well-known infectious agent; however, its role as a

foodborne organism was not detected until the early 1980s. Ex-

amples of emerging foodborne pathogens and possible causes of

emergence are provided in Table 41.4. The challenge posed by

the appearance of emerging pathogens is that these organisms

may not always behave as traditional pathogens. Therefore, new

control measures to ensure that foods are free of these pathogens

may be required.

CONTROL MEASURES FOR MICROBIAL

CONTAMINANTS

A combination of factors is normally responsible for occurrence

of an incident of foodborne illness. The pathogen must first

reach the food involved; the organism must survive until food is

ingested; in many cases, the organism must multiply to an infec-

tious level or produce toxins; and lastly, the host must be suscep-

tible to the level of organisms ingested with the food. Control

measures to ensure food safety include (1) prevention of con-

tamination of foods by pathogenic organisms (2) inhibition of

growth or elimination of pathogens in foods and food products.

The first stage of control measures is to prevent contamination of

food animals and plants during the production stage. Production

practices such as the use of manure and other organic fertil-

izer materials can provide the vehicle for contamination of food