Does Food Processing Increase Shelf Life & Reduce Spoilage?

What Causes Food to Spoil

• Fruits, vegetables, grains, dairy and meats available for consumption start the journey from producer to consumer in a raw state. Environmental factors influence the rate of decay of raw foods, including oxygen, temperature, humidity and exposure to moisture, and exposure to microorganisms and insects. Oxygen breaks down fats. Humidity and moisture encourages mold growth. Microorganisms break down the food, releasing internal moisture that allows for yeast and mold growth. If food is not properly protected through the use of processing and packaging, these factors come into play and the food spoils.

Canning Food

• Canning is the process of sealing foods within a vacuum to prevent exposure to any environmental factors that cause spoilage. Foods with high acidic content may be cooked and placed in jars, which are then processed in boiled water at 220 degrees F; the process is referred to as the boiling-water method. Homemade jellies and jams are examples of cooked foods preserved with canning. Some raw vegetables may be pickled and canned through the boiling-water method, such as okra or peppers. Another form of canning is pressure cooking, in which a pressure cooker forms the vacuum through pressurized steam. The jars, lids and lid rings must be sterilized and the processes followed according to temperature and food packing requirements to effectively prevent the development of mold and bacterial growth that cause spoilage.

Freezing Food

• Food may also be sealed and frozen to prevent spoilage and extend the shelf life. The below-freezing temperature inhibits mold growth and sealing prevents the freezing air from "burning" the food and destroying its nutritional value. Prepared foods, such as soups and stews, may also be frozen. To freeze vegetables, blanch the foods first by immersing them in boiling water for three to five minutes. Shock them to stop the cooking by placing them in a bowl of ice water. Allow the foods to dry thoroughly, seal and freeze. Use defrosted foods immediately to avoid illness, as defrosted foods are vulnerable to microbial activity.

Drying Food

• Drying foods removes the natural moisture content of the food. Mold requires moisture and the lack of moisture prevents mold growth. Dried foods are also less susceptible to spoilage from exposure to oxygen or temperature. Drying is basically preservation through dehydration. The foods must be exposed to high temperatures for extended periods of time to slowly draw the moisture out without scorching the foods. Drying may also require the application of a sulfite to prevent browning, such as when drying fruits and vegetables.