Preservation

Question 1

Why does food spoil?

Answer 1

Food spoils because of the action of enzymes, oxidation through exposure to air, and the action of microorganisms such a yeasts, molds & bacteria

Question 2

What is preservation?

Answer 2

the act of stopping or slowing down food spoilage

Question 3

What is the main cause of food spoilage?

Answer 3

micro organisms

Question 4

In what conditions do microorganisms multiply?

Answer 4

in warmth, moisture & for some, air

Question 5

What are some methods of preservation?

Answer 5

drying, heating, freezing, reducing temperature, removing air & adding chemicals

Question 6

How does drying prevent food spoilage?

Answer 6

it removes the moisture from food

Question 7

What are some techniques used to dry food in preservation?

Answer 7

drying can be done naturally using the sun and wind, by using solar dryers, by vacuum drying orby using streams of hot air

Question 8

Name 5 foods suitable for drying

Answer 8

meat, fish, milk, herbs, fruits, yam & cassava

Question 9

How does heating help to prevent food spoilage?

Answer 9

by heating food to a temperature high enough to kill microorganisms

Question 10

What are 2 preservation methods that require the use of heat?

Answer 10

Pasteurization & Sterilization

Question 11

How is heat treated food protected from recontamination?

Answer 11

by canning & bottling

Question 12

What are some foods that are suitable for canning and bottling?

Answer 12

meat, fish, vegetables, fruits, milk & soup

Question 13

How does freezing prevent food spoilage?

Answer 13

the growth of micro organisms slow down in cool conditions and it is stopped completely by deep freezing

Question 14

What are 3 methods of freezing?

Answer 14

plate freezing, blast freezing, immersion freezing

Question 15

What is blanching?

Answer 15

when food is immersed in boiling water before freezing it

Question 16

What are some suitable foods for freezing?

Answer 16

meat/poultry, fish, fruits & vegetables (all foods)

Question 17

What are the 4 general rules for preserving food?

Answer 17

1) make preserves when fruits & vegetables are plentiful

2) try to pick fruits on a dry day, wet fruits tend to become moldy quickly

3) choose fruits that are just ripe, over ripe fruits tend to ferment quickly

4) Always label your preserves, this allows you to use the older stocks first

Question 18

What are some chemical methods of preserving food?

Answer 18

sugar, salt & vinegar, smoking

Question 19

How does sugar prevent food spoilage?

Answer 19

the high percentage of sugar in jams & jellies makes water unavailable to microorganisms which then cannot grow.

Question 20

When a jar of jam/jelly is opened it goes moldy sometimes. Why is this so?

Answer 20

because the moisture from the air gets trapped and now microorganisms can grow there

Question 21

How is salt used as a preservative?

Answer 21

it can be used in a dry form, in water as groin with vinegar as a plain pickle

Question 22

How is smoke used as a preservative?

Answer 22

wood smoke coats the surface of food with chemicals that act as preservatives. It dries out the surface oof food slightly. By using this method food is only kept for a short period.