microbio test 4 questions Unit 8 – Flashcards

Which of the following determines whether or not a wine is considered to be dry? The amount of carbon dioxide after fermentation The type of grape used as a starting material The percentage of alcohol after fermentation The amount of free sugar after fermentation

☆The use of plastic film to wrap meat products can result in increased surface growth of microorganisms in part because of exposure to water carbon dioxide N2 which comprises approximately 78 % of gas in the atmosphere oxygen

The process of racking, used in the production of wines, involves addition of sulfites removal of sediments depressurizing bottles addition of carbon dioxide

Which of the following represents a different principle for food preservation? heating freeze-drying smoking addition of salt

Primary metabolites include bacteriocins and other similar cytotoxic compounds. include compounds such as antibiotics and mycotoxins. are compounds needed for the synthesis of microbial cells in the primary growth phase. are compounds that accumulate during the period after primary growth phase and have no direct relationship to the synthesis of cell materials.

☆Corynebacterium glutamicum is used for the large scale industrial production of amino acids polysaccharides antibiotics vitamin B1

In many ways, ______________ as a biofuel compares very favorably to ethanol and other fuels.

☆The major organism used in the microbial production of citric acid is Lactobacillus delbrueckii Penicillium notatum Aspergillus niger Rhizopus nigrificans

☆Microbially produced glycolipid surfactants are used for a. emulsification and increasing detergency, which aids in biodegradability b. both emulsification and increasing detergency and prevention or reduction of microbial growth on surfaces. c. solubilization of hydrophobic compounds, which enhances cleanup and recovery of oil from spills. d. both emulsification and increasing detergency and solubilization of hydrophobic compounds. e. prevention or reduction of microbial growth on surfaces, decreasing transmission of disease.

Feeding chickens a strain of Bacillus subtilis leads to a reduction in coliforms and Campylobacter in the processed carcasses increased body weight and feed conversion and a reduction in coliforms and Campylobacter in the processed carcasses increased body weight and feed conversion lower carriage of the pathogenic E. coli strain O157:H7 all of the choices

Which of the following is true about molecular methods of microorganism detection in foods? They can be used to detect the presence of a single specific pathogen. All of the choices are correct They can be used to detect viruses that are not easily cultured. They can be used to detect slow growing pathogens.

Food-borne pathogens are most commonly identified by standard culture techniques none of the choices pulsed-field gel electrophoresis polymerase chain reaction (PCR)

Production of semisynthetic penicillins involves chemical modification of a penicillin product after it has been released from penicillin producing cells. True False

☆Most biopolymers industrially produced by means of microorganisms are cell wall constituents histones nucleic acids polysaccharides

To assure maximum production of desired metabolites, it is always necessary to maintain organisms in active logarithmic growth. True False

☆Frequently a critical component in the medium, often the carbon source, is added _____________ so that the microorganisms will not have excess substrate available at any given time. continuously gradually sporadically none of the choices

Gamma irradiation has been used to sterilize certain types of foods. There are however, certain limitations on its effectiveness. One of these is that it will only work on it is effective with all foods moist foods dry foods foods that are not in metal cans

The conventional low-temperature holding procedure used in the pasteurization of milk involves holding the milk at 62.8o C for __________ minutes. 60 30 15 5

☆The process of beer lagering involves carbonation none of the choices distillation aging

☆Most antibiotics are produced by unicellular bacteria protozoa actinomycetes yeasts

Penicillin is produced by some actinomycetes protozoan fungi bacteria

☆A plasmid from the plant pathogenic bacterium ____________ ____________ is chiefly responsible for the successful genetic engineering of plants.

☆A microorganism that has been used in the production of sour mash whiskey is Lactobacillus delbrueckii Lactococcus lactis Saccharomyces cerevisiae Leuconostoc mesenteroides

In all cases, it is necessary for disease-causing microorganisms to grow in a food to result in disease transmission to humans. True False

☆Which of the following microbial genera is used in the production of fermented dairy products? Streptococcus Lactobacillus Leuconostoc all of the choices

☆The medium used in protoplast fusion experiments is isotonic none of the choices hypotonic hypertonic

Production of semisynthetic penicillins involves chemical modification of a penicillin product after it has been released from penicillin producing cells. True False

☆The approach of using mutagenesis and genetic selection to produce microbes with new degradative capabilities or the ability to produce compounds with new and unique properties is called ______________ evolution.

☆A major organism used in the biocontrol of a variety of types of insects is Bacillus subtilis Bacillus thuringiensis Clostridium botulinum Bacillus cereus

The swelling of a food-containing can is frequently due to the production of ___________ by spoilage microbes. all of the choices oxygen gas nitrogen gas carbon dioxide gas

Which of the following can function better at lower pH? viruses bacteria protozoa yeasts and molds

☆Mashing is a process involving carbonation carbohydrate hydrolyisis inoculation protein putrefaction

Lysozyme is an important antimicrobial substance found at high levels in which food? fish eggs fruits vegetables

☆Phenylacetic acid is added to the penicillin fermentation to allow incorporation of which side chain group? methyl benzyl propyl acetyl

☆Temperature and relative humidity are important intrinsic factors in determining the rate of food spoilage. True False

☆A major fungal genus that produces aflatoxin is Aspergillus Rhizopus Claviceps Penicillium Claviceps

☆A major advantage of protoplast fusion is the fact that the protoplast condition can easily be maintained indefinitely protoplasts of different microbial species can be fused all of the choices the microbes are rendered harmless by the process

☆The first penicillin-producing fungus that could be grown in stirred fermenters was Penicillium chrysogenum Penicillium notatum Aspergillus niger Pisolithus tinctorius

The production of natural carbon dioxide by yeasts after a wine is bottled results in brandy sweet wine dry wine champagne

Streptococcus thermophilus and Lactobacillus bulgaricus contribute to the flavor of yogurt by producing diacetyl during the fermentation of lactose. True False

☆Corynebacterium glutamicum is used to produce glutamic acid, and this is most successful when the cell permeability is not changed increased decreased isotonic