Food Preservation

Objectiveهدف

Identify methods to preserve food

Overviewمرور

Purpose

Food Preservation Techniques/Methods

Purpose

Foods are preserved to make them last longer and give foods the flavors/colors that are expected

Preserve = last longer

Refrigeration:

Slows down microorganism growth

Required temperature ranges are 0-5oC for refrigeration

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

Methods of Food Preservation

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

What about reducing Aw?

Dehydration

Removing water from a food

Dried Fruit

Smoking

Mild surface dehydration

Anti-microbial properties of smoke

Fermentation

Organic acid and other chemical production by bacteria and/or fungi in a food (these are “good” microbes in foods)

Examples are pickles

Methods of Food Preservation

Additives Organic acids

Manufacturers add acid directly to the foodPreserves food similar to fermentation – acid is added vs. made by bacteria

Methods of Food Preservation

Summary

Purpose

Food Preservation Techniques/Methods

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?

Questions?

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