How do you preserve garden vegetables?

Food prices are rising and so is the popularity of growing vegetables in a home garden. What are the best ways to preserve an abundance of vegetables to be enjoyed after the summer season is past? What are the safety issues that should be considered? What equipment is needed to safely preserve produce? These are some of the questions consumers ask, especially those who are canning or freezing foods for the first time

FREEZING VEGETABLES

Freezing is definitely a good option for those who have room in their freezer. Most vegetables need to be blanched to inactivate the enzymes that will otherwise cause the loss of color, flavor and nutrients. Harvested fresh, fruits and vegetables continue to undergo chemical changes that can cause spoilage and deterioration of the product. This is why these products should be frozen as soon after harvest as possible and at their peak degree of ripeness. Enzymes in the fruits and vegetables must be inactivated to prevent the loss of nutrients and color and flavor changes that will occur.

Enzymes are inactivated by the blanching process, which is the exposure of the vegetables to boiling water or steam for a brief period of time. The vegetable must then be cooled rapidly in ice water to prevent it from cooking. Contrary to statements in some publications on home freezing, in most cases blanching is absolutely essential for producing top-quality frozen vegetables. Blanching also helps to destroy microorganisms on the surface of the vegetable, brightens the color, helps retard loss of vitamins and helps make some vegetables, such as broccoli and spinach, more compact.

Rancid oxidative flavors may develop through contact of the frozen product with air. This problem can be prevented by using a wrapping material that does not permit air to pass into the product and by removing as much air as possible from the freezer bag or container before freezing.

CANNING VEGETABLES

Vegetables are low-acid foods and must be canned in a pressure canner unless they are pickled using a tested recipe. Clostridium botulinum is a microorganism that grows and produces a deadly toxin in low-acid foods when oxygen has been removed, as it is when foods are canned. Boiling water temperatures will not destroy the botulinum spores that grow in low-acid foods. The spores are killed at 240 °F or above when processed for the proper times in a pressure canner. This is why it is important to use tested recipes. Pressure canners that have a dial gauge should be tested annually for accuracy. Weighted gauge canners do not need to be tested each year.

There are two safe ways of canning, depending on the type of food being canned. These are the boiling water bath method and the pressure canner method.

The boiling water bath method is safe for fruits, tomatoes and picklesas well as jam, jellies and other preserves . In this method, jars of food are heated by being completely covered with boiling water (212 °F at sea level).

High-acid foods contain enough acid (ph of 4.6 or less) so that the Clostridium botulinum spores can't grow and produce their deadly toxin. High-acid foods include fruits and properly pickled vegetables. These foods can be safely canned at boiling temperatures in a boiling water bath.

Tomatoes and figs have ph values close to 4.6. To can these in a boiling water bath, acid in the form of lemon juice or citric acid must be added to them.

Pressure canning is the only safe method of canning low-acid foods (those with a ph of more than 4.6). These include all vegetables, meats, poultry and seafood. Because of the danger of botulism, these foods must be canned in a pressure canner. Jars of food are placed in 2 to 3 inches of water in a pressure canner and then heated to a temperature of at least 240 F. This temperature can only be reached in a pressure canner.