Food Microbiology lecture 17

Question 1

How do you sucsessfully dry a food?

Answer 1

You need to apply heat, reduce the humidity in the air, and circulate air around it.

Question 2

What foods can be sundried and which foods cannot?

Answer 2

High acid foods can while low acid food will get spoiled if done so.

Question 3

How does a convection oven work?

Answer 3

It uses the exhaust system and fan to circulate air around a food

Question 4

What two factors does the rate of drying depend upon?

Answer 4

1) Surface area of food

2) composition of food

Question 5

Why is slow drying bad?

Answer 5

It gives enough time for pathogenic bacteria to become resistant to heat.

Question 6

Describe freeze drying? Advantages Vs. Disadvantages:

Answer 6

Freeze drying is when food is frozen, and the frozen water in the food is sublimed.
Advantages: Solutes remain in their position preserving
-texture
-flavor
-color
Disadvantages:
-Very costly
-4-8 times as expensive as regular drying
-Requires double the amount of energy

Traditional drying causes solutes to move up to the surface where water is being evaportated from.