Deck 15: Guess Whos Coming to Dinner: Microorganisms and Food

Question 1

In what way is the production of vinegar different from the production of the fermented food products discussed in this chapter?

Answer 1

Unlike many of the products discussed in this chapter, vinegar is not a fermentation waste. Rather, a sugar containing liquid is first fermented by yeast. The yeast release ethyl alcohol as a fermentation waste. The ethyl alcohol is then converted to vinegar (acetic acid) by aerobic bacteria in the genus Acetobacter.

Question 2

In which of the following products does fermentation of the must occur?

A) cheese
B) bread
C) beer
D) wine
E) sauerkraut

Answer 2

D

Question 3

Probiotics are:

A) any microbially fermented food.
B) food items that are produced by aerobic bacteria.
C) hormones that are produced by bacteria.
D) products that contain living microorganisms, thought to be beneficial.
E) antibiotics added to animal feed to encourage more rapid growth.

Answer 3

D

Question 4

Which of the following is an example of single-cell protein?

A) yogurt
B) cheese
C) Spirulina
D) beer
E) summer sausage

Question 5

If you make homemade wine, which of the following accurately describes the relationship between sweetness and alcohol content?

A) The sweeter the wine, the higher the alcohol content.
B) The sweeter the wine, the lower the alcohol content.
C) The dryer the wine, the lower the alcohol content.
D) There is no specific relationship between sweetness and alcohol content.

Question 6

Microbial fermentation of food products occurs when the microorganisms are allowed to grow:

A) in an anaerobic environment.
B) in an aerobic environment.
C) in an acidic environment.
D) at low temperatures.
E) at high temperatures.

Question 7

In what way are microorganisms used in the production of coffee?

A) Extracts of coffee beans are fermented by bacteria.
B) Extracts of coffee beans are fermented by yeast.
C) Extracts of coffee beans are first fermented by yeast. Fermentation waste products released by the yeast are then converted in different products by aerobic bacteria.
D) Microorganisms that grow naturally on coffee beans provide the coffee with desirable flavors.
E) Bacteria are used to remove the coating of coffee beans prior to roasting.

Question 8

Of the following pairs of organisms, which two are most closely related to each other?

A) Brewers' yeast and Spirulina
B) Brewer's yeast and the Lactobacillus used in yogurt production.
C) Brewer's yeast and mushrooms
D) Penicillium camemberti and Lactobacillus
E) Penicillium camemberti and the Gram-positive bacteria used to make pickles.

Question 9

When baking bread, all of the following steps occur. In which answer are the steps presented in the correct order?

A) yeast is kneaded into dough » loaf is baked » yeast ferments » bread rises
B) loaf is baked » yeast is kneaded into dough » yeast ferments » bread rises
C) yeast is kneaded into dough » yeast ferments » loaf is baked » bread rises
D) loaf is baked » bread rises » yeast is kneaded into dough » yeast ferments
E) yeast is kneaded into dough » yeast ferments » bread rises » loaf is baked

Question 10

What is whey?

A) the semisolid milk product produced as a first step in cheese making
B) the remaining liquid following production of a semisolid milk product in cheese making
C) the sprouted barley used in beer making
D) the sugar-rich liquid portion that is produced in beer making, once starch has been degraded and remaining solids removed
E) the acid that is produced by bacteria during the production of sauerkraut

Question 11

The fermentation of most bread and alcoholic beverages relies on:

A) fermentation by Gram-positive bacteria.
B) fermentation by Gram-negative bacteria.
C) fermentation by single-celled fungi.
D) fermentation by filamentous fungi.

Question 12

Microbial fermentation only occurs under certain environmental conditions. Why, in terms of metabolism, do these organisms ferment under such conditions?

Question 13

Provide a biochemical explanation for why bread rises during its production.