1. Food Preservation

2. Objective هدف
Identify methods to preserve food

3. Overview مرور
Purpose
Food Preservation Techniques/Methods

4. Purpose Foods are preserved to make them last
longer and give foods the flavors/colors
that are expected
Preserve = last longer

5. Methods of Food Preservation
Refrigeration:
Slows down microorganism growth
Required temperature ranges are 0-5oC for refrigeration

6. Methods of Food Preservation
Freezing:
At temperatures < 0°C:
No microorganism growth
Chemical reactions are slowed
Frozen food will be kept frozen and stored at a product temperature of -17oC or below.
Note: Freezing is not a method of killing bacteria

7. Methods of Food Preservation
Heat Pasteurization
Killing the most resistant problematic microbes in the food
Heat pasteurization starts to kill pathogenic bacteria at 60°C

8. What about reducing Aw? Dehydration Removing water from a food
Dried Fruit
Smoking
Mild surface dehydration
Anti-microbial properties of smoke

9. Methods of Food Preservation
Fermentation
Organic acid and other chemical production by bacteria and/or fungi in a food (these are “good” microbes in foods)
Examples are pickles

10. Methods of Food Preservation
Additives
Organic acids
Manufacturers add acid directly to the food
Preserves food similar to fermentation – acid is added vs. made by bacteria

11. Summary
Purpose
Food Preservation Techniques/Methods

12. Review Questions
1. Why are foods preserved? 2. What is the purpose of refrigeration? 3. Is freezing a method to kill bacteria? 4. At what temperature does heat pasteurization start to kill bacteria? 5. What is an example of dehydrated food?

13. Questions?
سوالات