It appears that a lot of gardeners are planning to can a lot of fruit and vegetables this year. Home canning can provide safe, inexpensive, quality food if tested and approved methods are used. Otherwise, it may be better to forget it.
Organisms that cause food spoilage - molds, yeasts and bacteria - are always in the air, water and soil. Enzymes that may cause undesirable changes in flavor, color and texture are present in raw fruits and vegetables.
Home canners should not take shortcuts or be otherwise creative when canning, according to specialists. Using poor-quality fruits and vegetables or experimental canning techniques can result in botulism - a food poisoning that can kill.
When fruits and vegetables are canned, they must be heated hot enough and long enough to destroy the spoilage organisms and stop the action of enzymes.
A national survey conducted by the Department of Agriculture showed that many households used jars designed for home canning but one out of three also used peanut butter, coffee, and other kinds of jars, contrary to USDA recommendations.
Most canners used two-piece lids with new flat metal disks; one in ten, however, was reusing some flat disks, a practice also contrary to USDA advice.
Although the open-kettle method of canning is recommended only for jellies and as an initial step in preparing jams before water-bath processing, it was used by nearly half of those canning fruit and pickles, one-third of those canning tomatoes, and one out of seven canning vegetables. Also many canners were filling jars too tightly, a practice that can result in underprocessed foods.
Small berry and stone fruits, asparagus, green beans, beets, broccoli, corn and leafy greens, among others, should be preserved the day of harvest for highest quality. Apples, peaches, pears, plums and tomatoes, if harvested at firm maturity, should be ripened a few days before perserving them. Other fruits and vegetables may be stored for a week to months before preservation without significantly lowering their quality.
Removal of skins from thin-skinned foods such as tomatoes and peaches is important. A short blanching time in boiling water loosens the skins, and a short cooling time in cold or ice water stops the cooking of the food.
Because water leaches out vitamins, dilutes color and flavor, and results in a mushy product, don't let foods soak too long in either hot or cold water.
Tomatoes and tomato juice are less likely to separate if tomatoes are cut and heated at once.
While sugar is not needed to can fruits safely, it contributes to better color, flavor and texture. Likewise, vegetables may be safely canned without salt, but when salt is used, better flavor results.
Sugar concentration in syrups is important to the appearance of the fruit. With a light syrup, fruits are less likely to float than with a heavier syrup. And with a light syrup, fewer calories are added.
The Department of Agriculture has a free 100-page booklet, Home Food Preservation, which tells how to preserve the food from your garden. To get a copy, send a postcard to Consumer Information Center, Dept. 664G, Pueblo, Colorado 81009. CAPTION: Picture, no caption, By Ken Feil.