Chapter 28

To make commercial yogurt, which microorganism should be used for acid production? a. Streptococcus thermophilus b. Lactobacillus delbrueckii bulgaricus c. Penicillium mold d. Propionibacterium

a. Streptococcus thermophilus

Koji, used in Japan to make fermented soy products, is made up of __________. a. enzymes b. citric acid c. amino acids d. vitamins

a. enzymes

Aseptic packaging works to preserve foods through a. exposure to high heat. b. increasing pH. c. creation of an anaerobic environment. d/ mutation of bacterial DNA. e. creation of an anaerobic environment and high heat.

a. exposure to high heat

Which of the following organisms would you expect to produce significant amounts of gas while fermenting milk? a. Streptococcus b. Proprionibacterium c. Lactobacillus d. Aspergillus

b. Proprionibacterium

Spoilage of canned foods due to inadequate processing, NOT accompanied by gas production, is a. flat sour spoilage. b. thermophilic anaerobic spoilage. c. caused by acid-tolerant fungi. d. putrefactive anaerobic spoilage. e. spoilage by mesophilic bacteria.

a. flat sour spoilage

Which of the following statements is true regarding biofuels? a. Conventional ethanol has a lower capacity to absorb water than branched alcohols. b. Hydrogen is an attractive candidate as a fossil fuel replacement. c. Making ethanol from cellulose is much less expensive than making it from corn. d. One advantage of ethanol is that it can be transported by conventional gas pipelines.

b. Hydrogen is an attractive candidate as a fossil fuel replacement

Which of the following statements concerning putrefactive anaerobic food spoilage is FALSE? a. The contents of the can may be partially digested. b. The can is not swollen. c. There is a typical putrid odor. d. Clostridium sporogenes and C. botulinum are possible causative microbes.

b. The can is not swollen

Which of the following statements concerning bioreactors is FALSE? a. They can hold as much as 500,000 liters of liquid culture. b. They are designed to keep nitrogen soluble in water. c. They are designed with close attention to aeration and pH control. d. They are vessels used for industrial fermentation.

b. They are designed to keep nitrogen soluble in water

Which microbe is used in recovering otherwise unprofitable grades of copper ore? a. Ashbya gossypii b. Thiobacillus ferrooxidans c. Aspergillus niger d. S. cerevisiae

b. Thiobacillus ferrooxidans

The production of acetic acid in vinegar requires the use of ______. a. one type of yeast b. both yeast and bacteria c. only bacteria d. three different types of yeast

b. both yeast and bacteria

All of the following are fuels produced by microorganisms EXCEPT a. hydrogen. b. cellulose. c. methane. d. ethanol. e. oil from algae.

b. cellulose

Which of the following reactions makes wine less acidic? a. sugar → ethanol b. malic acid → lactic acid c. sugar → CO2 + H2O d. ethanol → acetic acid e. carbon dioxide → sucrose

b. malic acid → lactic acid

If an approximate dose of radiation of 10 to 50 kGy is used for industrial food preservation, what is the target for destruction? a. non-endospore-forming bacteria b. viruses c. bacterial endospores d. higher animals (whole body)

c. bacterial endospores

Canning works to preserve foods through a. mutation of bacterial DNA. b. exposure to high heat. c. creation of an anaerobic environment and high heat. d. creation of an anaerobic environment. e. increasing pH.

c. creation of an anaerobic environment and high heat

All of the following are uses for radiation EXCEPT a. sterilizing spices. b. inactivation of Trichinella larvae. c. heating cold food. d. killing of insect eggs and larva. e. prevention of sprouting.

c. heating cold food

Industrial food preservation __________. a. uses very low doses of radiation (less than 1 kGy) on meats and poultry b. uses high doses of radiation to inhibit sprouting in stored potatoes c. includes the use of low doses of radiation for killing insects d. may use pasteurizing doses of radiation to sterilize the bacterial population of spices

c. includes the use of low doses of radiation for killing insects

Which of the following pertains to an improperly canned food product on a store shelf that bulges from microbial activity? a. thermophilic anaerobic spoilage b. hydrogen sulfide spoilage c. mesophilic spoilage d. bacterial soft rot e. flat sour spoilage

c. mesophilic spoilage

All of the following are industrial products produced using microbial fermentations EXCEPT a. citric acid. b. riboflavin. c. saccharin. d. monosodium glutamate. e. aspartame.

c. saccharin

Which of the following reactions is performed by yeast in wine-making? a. ethanol → acetic acid b. carbon dioxide → sucrose c. sugar → ethanol d. malic acid → lactic acid e. sugar → CO2 + H2O

c. sugar → ethanol

Which statement does NOT apply to secondary metabolites? a. They are not produced until the microbe has largely completed its logarithmic growth curve. b. They may be metabolic products of the original growth medium that the microorganism makes only when present at high density. c. The production curve follows the cell population curve almost in parallel. d. They are produced where the microbe has completed trophophase.

c. the production curve follows the cell population curve almost in parallel

Commercial sterilization of processed canned foods uses a 12D treatment which is based upon a theoretical population of 1012 C. botulinum endospores in a can of food. After treatment, there would theoretically be how many endospores left? a. 10 endospores b. 100 endospores c. 12 endospores d. 1 endospore e/ 0 endospores

d. 1 endospore

Microorganisms of which genus play a significant role in the production of both soy sauce and yogurt? a. Streptococcus b. Aspergillus c. Saccharomyces d. Lactobacillus

d. Lactobacillus

Canning preserves food a. by exposure to radiation. b. by exposure to chemicals. c. through use of aseptic packaging. d. by exposure to high heat. e. by exposure to high pH.

d. by exposure to high heat

A canned product is subjected to 12D treatment. One of the cans is leaky and causes a disease outbreak in a restaurant. The offending microorganism is later found to be a mesophilic non-spore-forming bacterium. When is the can most likely to have become contaminated? a. during sterilization in the retort b. The organism was already present on the food and was incorporated during packaging. c. during transport d. during cooling

d. during cooling

Commercial sterilization differs from complete sterilization in that commercial sterilization a. employs a higher temperature. b. may result in the survival of fungal spores. c. kills only bacteria. d. may result in the survival of thermophiles. e.kills all microorganisms.

d. may result in the survival of thermophiles

Which of the following is an undesirable contaminant in wine-making? a. Clostridium b. Saccharomyces c. lactic acid bacteria d. Bacillus e. Acetobacter

e. Acetobacter

Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to filling with food? a. X rays b. hot HCl solution c. gamma radiation d. autoclave e. hot hydrogen peroxide solution

e. hot hydrogen peroxide solution