Monday, July 13, 2015

Preserving the Harvest

Home food preservation treats foods in a way that delays its spoilage, makes raw products more stable so they can last longer, and allows seasonal foods to be available all year long. It also allows you more control over food, gives you a way to connect with previous generations, save money, and have fun in the process.

Spoilage: process of food becoming unsafe or unacceptable for human consumption. Major causes of  food spoilage include: microorganisms (germs, mold, yeast), enzymes in fruit and vegetables, bruising and cuts in fresh produce, and insect damage.

When the conditions are right, germs multiply fast!

  Time # of bacteria
  Start 1
  30 minutes 4
  1 hour 16
  1.5 hours 64
  2 hours 256
  2.5 hours 1,024
  3 hours 4,096
  3.5 hours 16,384
  4 hours 65,536

Food safety is critical when preserving food at home. Follow researched-based, tested recipes and choose the right method of food preservation to reduce spoilage such as, refrigeration, freezing, canning, sweetening and acidifying jellies and jams, pickling and fermenting, and drying. If food preservation is not done right, food spoilage and/or a foodborne illness can happen.

Refrigeration will slow the growth of germs and other microorganisms and slows down the action of fruit and vegetable enzymes that cause spoilage, however it will not preserve foods for a long periods of time. Keep your refrigerator at 40 degrees or cooler to preserve food longer.

Freezing is the easiest method of food preservation and is a safe method for any food. Freezing stops germs from growing, but it does not kill them, and it slows enzyme activity; but it doesn't stop them; blanching stops the enzymes. Keep your freezer at zero degrees or cooler to get the most out of preservation.

Canning when done right, kills the germs and causes a vacuum that seals the lids. There are two types of canning: boiling water bath and pressure canning. The pH of a food determines which canning method to use. If proper canning methods are not followed, it can lead to food spoilage or serious foodborne illness.

Sweetening and acidifying (jams and jellies) use sugar which prevents the growth of germs. It binds with water so germs can't use it. Lemon juice and/or citric acid are used to add flavor and helps gel formation. Long-term storage of jams and jellies requires canning.

Pickling uses acids (naturally present or added) to lower the pH of a food. This prevents the growth of germs that cause food to spoil and/or foodborne illness. Long-term storage will require processing/canning.

Drying is the oldest method of food preservation. It removes water from food such as fruit, vegetables, herbs, and meat. Removing the water prevents germ growth. Dried foods must be packed in moisture-proof containers so they do not become rehydrated.

Now you may be asking, "which method do I choose?" The following diagram may help

Canning Freezing Drying
Equipment ($) Canners, jars, and lids Freezer and stroage containers dDehydrator or oven and strorage containers
Energy Requirement Fairly low High (due to freezer) Low if using a dehydrator; high for oven use
Preparation Time Long Medium Short
Processing Time Medium to Long Short Long
Does it look like the fresh food? Somewhat Yes Somewhat
Do you lose nutrients? Loss of vitamins     A & C Not much Some loss of vitamin A & C

Source: University of Georgia, So Easy to Preserve, 5th ed.

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