1. Food Microbiology is the study of:
(A) Chemical reactions in food
(B) Microorganisms that grow, live, or affect food
(C) Physical properties of food
(D) Food machinery
2. The scientist known as the “Father of Microbiology” is:
(A) Louis Pasteur
(B) Robert Koch
(C) Alexander Fleming
(D) Joseph Lister
3. Which microorganism is responsible for curd formation from milk?
(A) Bacillus cereus
(B) Clostridium botulinum
(C) Streptococcus pyogenes
(D) Lactobacillus bulgaricus
4. The microorganism used in bread fermentation is:
(A) Lactobacillus
(B) Saccharomyces cerevisiae
(C) Penicillium notatum
(D) Aspergillus niger
5. The bacteria responsible for food poisoning in improperly canned foods is:
(A) Clostridium botulinum
(B) Escherichia coli
(C) Salmonella enteritidis
(D) Staphylococcus aureus
6. Yeasts are classified as:
(A) Bacteria
(B) Viruses
(C) Fungi
(D) Protozoa
7. Which of the following is a mold?
(A) Salmonella
(B) Rhizopus
(C) Vibrio
(D) E. coli
8. The microorganism responsible for alcohol fermentation is:
(A) Aspergillus
(B) Penicillium
(C) Saccharomyces cerevisiae
(D) Lactobacillus
9. The optimum temperature for the growth of most bacteria is:
(A) 0°C
(B) 25°C
(C) 50°C
(D) 37°C
10. Pathogenic bacteria are those that:
(A) Cause spoilage
(B) Ferment food
(C) Preserve food
(D) Cause disease
11. Which of the following microorganisms is used for the production of vinegar?
(A) Acetobacter aceti
(B) Clostridium botulinum
(C) Streptococcus thermophilus
(D) Penicillium chrysogenum
12. The main cause of food spoilage is:
(A) Packaging
(B) Microbial activity
(C) Freezing
(D) Dehydration
13. The bacterial endospores are resistant to:
(A) Oxygen only
(B) Light only
(C) Heat and drying
(D) Enzymes
14. The most heat-resistant pathogen found in canned foods is:
(A) Listeria monocytogenes
(B) Salmonella typhi
(C) Vibrio cholerae
(D) Clostridium botulinum
15. The microorganism used in yogurt production is:
(A) E. coli
(B) Streptococcus thermophilus
(C) Bacillus subtilis
(D) Clostridium tetani
16. The pH range for bacterial growth is generally between:
(A) 1–3
(B) 4–9
(C) 10–12
(D) 13–14
17. The group of microorganisms that can grow in cold temperatures is called:
(A) Mesophiles
(B) Thermophiles
(C) Psychrophiles
(D) Halophiles
18. Molds reproduce mainly by:
(A) Spore formation
(B) Budding
(C) Binary fission
(D) Conjugation
19. The spoilage of canned food without gas formation is caused by:
(A) Proteolytic bacteria
(B) Coliform bacteria
(C) Lactic acid bacteria
(D) Flat sour bacteria
20. The most common method to destroy microorganisms in food is:
(A) Heating
(B) Freezing
(C) Filtration
(D) Drying
21. The bacteria responsible for souring of milk is:
(A) Clostridium
(B) Salmonella
(C) Lactobacillus
(D) Bacillus
22. Which microorganism is used in the production of blue cheese?
(A) Rhizopus stolonifer
(B) Aspergillus flavus
(C) Penicillium roqueforti
(D) Candida albicans
23. Food poisoning by Staphylococcus aureus is caused by:
(A) Endotoxins
(B) Exotoxins
(C) Fungal spores
(D) Enzymes
24. The bacteria responsible for cholera is:
(A) Vibrio cholerae
(B) Salmonella typhi
(C) Shigella flexneri
(D) E. coli
25. The microorganisms that can tolerate high salt concentration are:
(A) Thermophiles
(B) Halophiles
(C) Psychrophiles
(D) Mesophiles
26. Which of the following food items is most likely to support microbial growth?
(A) Dried fruits
(B) Fresh meat
(C) Salted fish
(D) Canned food
27. The enzyme responsible for milk clotting in cheese making is:
(A) Lipase
(B) Amylase
(C) Rennin
(D) Catalase
28. The microorganism used for citric acid production is:
(A) Aspergillus niger
(B) Rhizopus nigricans
(C) Penicillium notatum
(D) Candida tropicalis
29. The presence of coliform bacteria in food indicates:
(A) Fecal contamination
(B) Spoilage
(C) High acidity
(D) Lack of oxygen
30. Botulism toxin affects which part of the body?
(A) Digestive system
(B) Nervous system
(C) Respiratory system
(D) Circulatory system
31. The microorganism used for penicillin production is:
(A) Mucor mucedo
(B) Aspergillus flavus
(C) Candida albicans
(D) Penicillium notatum
32. The bacterial count of milk can be measured by:
(A) Centrifugation
(B) Titration
(C) Standard Plate Count method
(D) Refractometer
33. The optimum growth temperature for thermophilic bacteria is:
(A) 0–20°C
(B) 25–40°C
(C) 45–70°C
(D) Above 90°C
34. The process of using microorganisms to preserve food is called:
(A) Pasteurization
(B) Fermentation
(C) Irradiation
(D) Blanching
35. The bacteria responsible for typhoid fever is:
(A) Salmonella typhi
(B) Vibrio cholerae
(C) E. coli
(D) Shigella dysenteriae
36. The growth of molds is favored by:
(A) Low moisture
(B) Low oxygen
(C) High sugar
(D) High acidity
37. The microorganism that grows best in the absence of oxygen is:
(A) Aerobe
(B) Anaerobe
(C) Facultative aerobe
(D) Microaerophile
38. The production of sauerkraut involves:
(A) Alcoholic fermentation
(B) Acetic acid fermentation
(C) Lactic acid fermentation
(D) Butyric acid fermentation
39. The main spoilage organism in bread is:
(A) Clostridium
(B) Aspergillus
(C) Penicillium
(D) Rhizopus
40. The toxin produced by Aspergillus flavus is:
(A) Botulinum toxin
(B) Endotoxin
(C) Aflatoxin
(D) Cytotoxin
41. The bacteria responsible for souring of bread dough is:
(A) E. coli
(B) Streptococcus
(C) Bacillus
(D) Lactobacillus
42. The common preservative used to prevent microbial spoilage in soft drinks is:
(A) Sodium benzoate
(B) Citric acid
(C) Vinegar
(D) Salt
43. The destruction of all forms of microbial life including spores is called:
(A) Disinfection
(B) Pasteurization
(C) Sterilization
(D) Cleaning
44. Which microorganism is used for the production of vitamin B12?
(A) Clostridium botulinum
(B) Lactobacillus bulgaricus
(C) Streptococcus lactis
(D) Propionibacterium shermanii
45. The pH below which most bacteria stop growing is:
(A) 3.0
(B) 4.5
(C) 5.0
(D) 6.5
46. The process used to make pickles shelf-stable is:
(A) Blanching
(B) Freezing
(C) Acid fermentation
(D) Smoking
47. The microorganism responsible for the slimy texture in spoiled meat is:
(A) Bacillus
(B) Pseudomonas
(C) Lactobacillus
(D) Clostridium
48. The shelf life of pasteurized milk is shorter because:
(A) It contains preservatives
(B) It absorbs moisture
(C) It has high fat
(D) Some microorganisms survive pasteurization
49. The most common indicator organism for water quality testing is:
(A) Salmonella
(B) Clostridium
(C) Bacillus
(D) E. coli
50. The study of microorganisms beneficial in food production is called:
(A) Environmental Microbiology
(B) Medical Microbiology
(C) Industrial Microbiology
(D) Agricultural Microbiology