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

Which of the following organisms is used in the baking industry?

  1. Yeast

  2. Rhizopus

  3. Green algae

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

Yeast (Saccharomyces cerevisiae) is a fungus used in baking because it ferments sugars present in dough, producing carbon dioxide gas that makes the bread rise and become fluffy. Rhizopus is a mold that causes rotting, green algae are photosynthetic organisms not used in baking, and Penicillium is used for antibiotic production, not baking.

Multiple choice

Which of the following organisms is used to convert milk into curd?

  1. Mycobacterium

  2. Salmonella

  3. Lactobacillus

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

Lactobacillus is the bacteria that converts milk into curd (yogurt) by fermenting lactose (milk sugar) into lactic acid. This acid causes milk proteins to coagulate, forming curd. Mycobacterium causes TB, Salmonella causes food poisoning, and Penicillium is a fungus used for antibiotic production.

Multiple choice

Which of the following organisms is used in the preparation of alcohol?

  1. Mushroom

  2. Mucor

  3. Yeast

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

Yeast (Saccharomyces cerevisiae) is used in alcohol production through fermentation. It converts sugars into ethanol and carbon dioxide. Mushrooms are fungi used for food, Mucor is a bread mold, and algae are photosynthetic organisms - none produce alcohol through fermentation. Yeast's ability to ferment sugars makes it essential in brewing and winemaking.

Multiple choice

Which of the following statements is true?

  1. Propionibacterium can use lactic acid produced by other bacteria.

  2. Pseudomonas is oxidase negative.

  3. Escherichia is oxidase positive.

  4. Salmonella can be readily distinguished from E. coli by the production of lactic acid.

  5. All bacteria have cytochrome C.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is true. Propionibacteria can transform lactic acid to pyruvic acid in preparing for the Kreb’s cycle.

Multiple choice

Why is Lactobacillus cariogenic?

  1. It is acidogenic and aciduric.

  2. It is most abundant in saliva.

  3. It is the only acidogenic bacteria in the oral cavity.

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lactobacillus is both acidogenic and aciduric bacteria and therefore causes caries. Acidogenic bacteria are acid-producing bacteria. The acid produced damages dentin and other mineralized structures of teeth. Acidouric bacteria are bacteria that can grow well in acidic medium.

Multiple choice

Consider the following statements:

  1. Fruit juices turn bitter in taste if they are kept in open place for some time because bacteria of the atmosphere react with the juices.
  2. Organisms which give birth to young ones directly are viviparous animals.

Which of the given statements is/are correct?

  1. Only (1)

  2. Only (2)

  3. Both (1) and (2)

  4. Neither (1) nor (2)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statement (1) is incorrect. Fruit juices turn bitter in taste if they are kept in open place for some time because of fermentation of juice by yeast. Statement (2) is correct. Organisms which give to birth to young ones directly are viviparous animals. For example, dogs, cats, etc.

Multiple choice

Which of the following options is a physical change?

  1. Browning of apple

  2. Souring of milk

  3. Sublimation of ammonium chloride

  4. Preparation of curd
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Physical change is affecting the form of a chemical substance, but not its chemical composition. It can be reversed.

Multiple choice

Consider the following statements:

  1. Yakult, a probiotic drink is a product made by mixing skimmed milk with a special strain of the bacterium.
  2. An adult body has approx. 89% of water.

Which of the given statements is/are correct?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Statement (1) is correct. Yakult is a milk-like product made by fermenting a mixture of skimmed milk with a special strain of the bacterium named Lactobacillus casei Shirota. Statement (2) is incorrect. An adult body has approx. 70% of water.

Multiple choice

Which of the following microbes are used in preparation of yoghurt?

  1. Lactobacillus bulgaricus and Streptococcus thermophilus

  2. Leuconostoc mesenteroids and Enterobacter aerogenes

  3. Enterobactor aerogens and Fusarium moniliforme

  4. Streptococcus lactis and Leuconostoc citrovorus

  5. Fusarium moniliforme and Streptococcus thermophilus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yoghurt is prepared by fermenting artificially concentrated milk with a mixture of Lactobacillus bulgaricus and Streptococcus thermophilus at a temperature of 24-5 oC for 4 hrs followed by fermentation with yeast.