Biology

Microorganisms in Food Production

1,086 Questions

Microorganisms play a vital role in food production through processes like fermentation and bioprocessing. Questions on this topic cover the use of yeast, bacteria, and industrial microbiology. These concepts are important for science sections in various competitive exams.

Alcoholic fermentationDairy beverage productionIndustrial ethanol preparationCitric acid productionBiodigester temperature

Microorganisms in Food Production Questions

Multiple choice

Sausage making is a traditional food preservation technique used by people. The microorganisms used to ripen the surface of sausages are ___________.

  1. S. pastorianus

  2. S. cerevisiae

  3. P. camemberti

  4. P. nalgiovense

  5. P. roqueforti
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 P. nalgiovense are used to ripen the surface of sausages. The mould cultures develop the aroma and improve the texture of the sausages. They also contribute to shortening of the ripening period and preserving the natural quality.

Multiple choice

Which among the following organic acids is fermented by both bacteria and fungi?

  1. Citric acid

  2. Lactic acid

  3. Gluconic acid

  4. Butyric acid

  5. Acetic acid
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It was the first organic acid to be produced from the microbial fermen­tation in starchy and sugary medium. Lactic acid fermentation is carried out by both bacteria (e.g. Streptococcus lactis and Lactobacillus species) and fungi (e.g. Rhizopus). The acid de­rived from fungal sources is costlier but is of high purity.  

Multiple choice

Which among the following statements does not characterise the process of fermentation in winemaking?

  1. During fermentation, heat is produced.

  2. If the temperature is kept below fermentation point for a day or two, then the maceration of wine takes place.

  3. Wild yeast begins the fermentation immediately.

  4. The yeast also produces esters and other compounds, which contribute to the wine’s fruity aromas.

  5. It is a common practice to add a sufficiently large dose of a single strain of yeast to start the fermentation.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Wild yeast can take up to a week to begin the fermentation because their initial populations are small compared to an inoculated fermentation.

Multiple choice

Directions: Choose a suitable option to fill in the blank:

Vintners produce wine by crushing grapes, fermenting the juice, and then— it for several months.

  1. to store

  2. store

  3. be stored

  4. storing
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The verb forms must be parallel: "crushing," "fermenting," and then "storing" are all gerunds. "To store" (infinitive) doesn't match the pattern. "Store" and "be stored" would break the grammatical structure of the list.

Multiple choice

The process during which pyruvic acid is converted into ethyl alcohol or organic acids is called as

  1. fermentation

  2. glycolysis

  3. photosynthesis

  4. aerobic respiration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fermentation is the anaerobic process where pyruvic acid is converted into ethyl alcohol (as in yeast) or organic acids (as in lactic acid fermentation). Glycolysis occurs earlier to produce pyruvic acid, while photosynthesis produces glucose. Aerobic respiration requires oxygen and produces CO2 and water, not alcohol.

Multiple choice

Process involved in the conversion of milk to curd is

  1. oxidation

  2. dehydration

  3. hydrogenation

  4. fermentation

  5. hydration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Milk converts to curd (yogurt) through fermentation by lactic acid bacteria (primarily Lactobacillus species). Oxidation involves electron loss, dehydration removes water, hydrogenation adds hydrogen, and hydration adds water - none of these describe the microbial action that curdles milk.

Multiple choice

Vinegar is obtained from the fermentation of ethanol. Its key ingredient is

  1. abietic acid

  2. paracetamol

  3. acetone

  4. acetic acid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Acetic acid is a colourless liquid that when undiluted is also called glacial acetic acid. As the main component of vinegar, it has a distinctive sour taste and pungent smell. Although it is classified as a weak acid, acetic acid is highly dangerous to skin.

Multiple choice

The flavour of raspberries is due to ________ compound.

  1. ethyl formate

  2. 2-ethylhexanol

  3. ethynol

  4. eugenol
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ethyl formate is an ester formed when ethanol (an alcohol) reacts with formic acid (a carboxylic acid). It is also known as ethyl methanoate because formic acid is also known as methanoic acid. Ethyl formate has the characteristic smell of rum and is also partially responsible for the flavour of raspberries.

Multiple choice

Pasteurisation is the progress in which milk is heated to _____.

  1. 600 C for 10 minutes

  2. 630 C for 20 minutes

  3. 630 C for 30 minutes

  4. 720 C for 10 minutes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pasteurization is a heat treatment process that kills harmful bacteria. Low-temperature pasteurization uses 63°C for 30 minutes, which is sufficient to eliminate pathogens while preserving milk quality. This method is also known as batch pasteurization.

Multiple choice

Enzyme lipolase produced by fungus Humicola languinosa effectively removes fat stains from fabrics but the yield obtained through this fungus is very less. To increase the yield, the gene for lipolase was isolated and cloned in another organism. Which of the following organisms was used for this cloning?

  1. Zygosaccharomyces rouxii

  2. Saccharomyces cerevisae

  3. Aspergillus oryzae

  4. Rhizopus sps
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The gene responsible for lipolase was isolated, cloned and inserted into Aspergillus oryzae. It is preferred due to rapid growth and strong secretion of enzymes.