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Question

1. The consumption of food containing pathogenic microorganisms—those capable of
causing disease—results in food infections. The microorganisms that most commonly cause food infections are bacteria and viruses; however, other tiny organisms and nonliving

particles can also contaminate foods.

2. Bacteria are microorganisms that lack a true cell nucleus and reproduce either by division or by forming spores. Many thrive in the intestines of birds and mammals, including poultry, pigs, and cattle, so foodborne infection often results from consuming undercooked or raw meats, foods contaminated with juices from raw meats, or produce,
milk, or water contaminated with infected animal feces. Bacteria cause about 39% of all foodborne illnesses. Of the most common bacterial causes of foodborne illness, the bacterium responsible for the most illnesses, hospitalizations, and deaths is Salmonella.
3. Viruses are much smaller than bacteria, and they can’t survive apart from living cells. Just one type, called norovirus, causes nearly all foodborne viral illness in the United States and 58% of all foodborne illness from any known cause; it is responsible for more foodborne illness than all other viruses, bacteria, and parasites combined. Norovirus is so
common and contagious that many people refer to it simply as “the stomach flu.”

Norovirus illness typically comes on suddenly and results in stomach cramps, vomiting, and diarrhea. In healthy people, the symptoms typically resolve spontaneously in a day or two. Raw foods can harbor norovirus, and it can spread from person to person. Hepatitis A and hepatitis E viruses also commonly contaminate food during harvesting, processing, or preparation. They can cause acute liver damage and even death.
4. Parasites are microorganisms that simultaneously derive benefit from and harm their
host. They are responsible for only about 2% of foodborne illnesses. The most common culprits are helminths (multicellular worms such as tapeworms, flukes, and roundworms)
and protozoa (single-celled organisms that commonly cause waterborne illnesses).

5. Fungi are plantlike, spore-forming organisms that can grow as either single cells or multicellular colonies. Two types of fungi are yeasts, which are globular, and molds, which
are long and thin. Less than 1% of foodborne illnesses are caused by fungi. This is due in
part to the fact that very few species of fungi cause serious disease in people with healthy immune systems, and those that do cause disease in humans are not typically foodborne. In addition, unlike bacterial growth, which is invisible and often tasteless, fungal growth

typically makes food look and taste so unappealing that we immediately discard it.

a. What types of microorganisms cause the most food infections?
b. Define pathogenic microorganisms and give three examples.
c. Which bacterium is responsible for the most illnesses, hospitalizations, and deaths?
d. Evaluate the importance of educating the public about the threat of foodborne illnesses.

Answer 1

d. Evaluate the importance of educating the public about the threat of foodborne illnesses.