Microbial Food Production

Question 1

Glucose –>

Answer 1

ethanol + carbon dioxide

Question 2

Why does ethanol not remain in the bread after baking?

Answer 2

Because of the high temperatures

Question 3

What is the cooling jacket in an industrial fermenter used for?

Answer 3

Removes heat energy, stopping the fermenter overheating and enzymes denaturing.

Question 4

What is the air filter in an industrial fermenter used for?

Answer 4

Filters air coming, maintaining sterile conditions.

Question 5

What are the stirrers in an industrial fermenter used for?

Answer 5

Keeps the broth well stirred to oxygenate all parts of the fermenter and prevent micro-organisms settling.

Question 6

What is the growth medium in an industrial fermenter used for?

Answer 6

Contains all necessary glucose and amino acids for micro organism growth.

Question 7

What is the super heated steam in an industrial fermenter used for?

Answer 7

Applied before the fermenter is used killing unwanted micro-organisms. Leaves only water with no other residue.

Question 8

What bacterium is used to make yoghurt?

Answer 8

Lactobacillus bulgaricus

Question 9

After the milk has been heated and cooled, why is the mixture maintained at 46 degrees once the lactobacillus is added?

Answer 9

It ensures that the bacteria’s enzymes are not denatured.

Question 10

Describe the method for yoghurt production.

Answer 10

1. The equipment is sterilised
2. The milk is pasteurised by heating
3. The bacterial culture is added to the cooled milk and left at 46 degrees for about four hours
4. Finally the yoghurt is further cooled to 5 degrees to preserve the yoghurt

Question 11

What gives yoghurt its texture and flavour?

Answer 11

Lactobacillus respires anaerobically producing lactic acid. This lowers the pH, acting as a preservative. The acid coagulates the milk protein as the acidic conditions change the shape of the proteins.