Chapter 28 MULTIPLE CHOICE Choose the one alternative that best completes the statement or answers the question 1 All of the following are advantages of a bioreactor instead of a flask culture EXCEPT A uniform aeration and mixing B larger culture volumes can be grown C instrumentation for monitoring environmental conditions D aseptic sampling E None of the answers is correct all of these are advantages of using a bioreactor instead of a flask culture Answer E 2 Spoilage of canned foods due to inadequate processing NOT accompanied by gas production is A putrefactive anaerobic spoilage B spoilage by mesophilic bacteria C thermophilic anaerobic spoilage D caused by acid tolerant fungi E flat sour spoilage Answer E 3 All of the following are industrial products produced by microbes EXCEPT A vitamin B12 and riboflavin B uranium C antibiotics D industrial enzymes E amino acids in food supplements Answer B 4 Which of the following pairs is mismatched A Lactobacillus yogurt B Acetobacter vinegar C Propionibacterium Swiss cheese D Penicillium blue cheese E Bacillus beer Answer E 5 All of the following are uses for radiation EXCEPT A prevention of sprouting B heating cold food C sterilizing spices D inactivation of Trichinella larvae E killing of insect eggs and larva Answer B 1 6 Which of the following microorganisms is usually used in the fermentation of alcoholic beverages A Saccharomyces B Penicillium C Rhizopus D Propionobacterium E Lactobacillus Answer A 7 Microorganisms play an active role in the formation of industrial products Which of the following is mismatched A Penicillium treatment of disease B Rhizobium increases nitrogen in the soil C Bacillus thuringiensis insecticide D algae citric acid E Saccharomyces cerevisiae for fermentation Answer D 8 What process does yeast use to produce ethanol for automobile fuel from corn A oxidation B anaerobic respiration C the Krebs cycle D fermentation E photosynthesis Answer D 9 The following steps are required for making cheese What is the second step A inoculation with Penicillium B inoculation with lactic acid bacteria C fermentation of curd D separation of curds and whey E enzymatic coagulation of milk Answer B 10 Aseptic packaging works to preserve foods through A mutation of bacterial DNA B creation of an anaerobic environment C creation of an anaerobic environment and high heat D increasing pH E exposure to high heat Answer E 11 Xanthan used in household products is produced by bacteria A that are plant pathogens B selected for their ability to utilize lactose C that were irradiated to mutate them D that were genetically modified E selected for their ability to utilize lactose and that are plant pathogens Answer E 2 12 What will be produced if wine is aerated A acetic acid B CH4 C CO2 H2O D ethanol CO 2 E None of the answers is correct Answer A 13 Which of the following is an undesirable contaminant in wine making A lactic acid bacteria B Saccharomyces C Bacillus D Acetobacter E Clostridium Answer D 14 Bioreactors are widely used for industrial fermentation Which of the following conditions must be closely monitored for optimal fermentation A pH B oxygen levels C temperature D both temperature and pH E temperature pH and oxygen levels Answer E 15 Which of the following reactions is performed by yeast in wine making A sugar CO 2 H2O B ethanol acetic acid C carbon dioxide sucrose D malic acid lactic acid E sugar ethanol Answer E 3 Figure 28 1 16 In Figure 28 1 assume the cells are your desired product and you want to maintain a continuous culture When would you harvest cells to maximize your yield A a B b C c D d Answer B 17 Commercial sterilization of processed canned foods uses a 12D treatment which is based upon a theoretical population of 10 12 C botulinum endospores in a can of food After treatment there would theoretically be how many endospores left A 1 endospore B 12 endospores C 10 endospores D 100 endospores E 0 endospores Answer A 18 A baker forgets to put yeast in his bread dough Which of the following do you expect to happen to the bread as a result A The bread will have a sour taste B The bread will not rise C It will take longer to bake D Bacterial contaminants will now be able to grow E The bread will look normal but will be tough Answer B 19 Aseptic packaging utilizes which of the following to sterilize laminated paper or plastic prior to filling with food A gamma radiation B autoclave C hot HCl solution D hot hydrogen peroxide solution E X rays Answer D 20 You are growing Bacillus subtilis in a bioreactor and notice that the growth rate has slowed and the pH has decreased What could you add A glucose B oxygen C peptides D lactose E lactic acid Answer B 4 21 As cheese ages it gets A saltier B more whey C more acidic D more alcoholic E more protein Answer C 22 Radiation works to preserve foods through A exposure to high heat B creation of an anaerobic environment and high heat C increasing pH D lethal mutation of bacterial DNA E creation of an anaerobic environment Answer D 23 Biomass is a renewable energy source derived from the organic matter produced by living organisms All of the following are sources of biomass EXCEPT A crops B landfill sites C bacteria D oxidation of metals E algae Answer D 24 What role do lactic acid bacteria play in cheese production A curd formation B ripening the cheese C providing characteristic flavor and smell D production of holes in Swiss cheese E Lactic acid bacteria carry out each of these roles in cheese production Answer E 25 Commercial sterilization differs from complete sterilization in that commercial sterilization A kills all microorganisms B may result in the survival of thermophiles C may result in the survival of fungal spores D kills only bacteria E employs a higher temperature Answer B 26 Which of the following microbes produces a natural biopesticide A Lactobacillus buggaricus B Penicillium chryssogenum C Saccharomyces cerevisiae D Thiobacillus ferroxidans E Bacillus thuringiensis Answer E 5 27 All of the following are true of irradiation methods used for food preservation and sterilization EXCEPT A they prolong shelf life of fruits and vegetables B ionizing radiation such as X rays or gamma rays is used C they are used for the sterilization of many spices D residual radioactivity is left behind on many foods E they greatly reduce the number of pathogens present in meats and poultry Answer D 28 All of the following are industrial products produced using microbial