Phone calls are coming into the office on a regular basis — yes, the wonderful tradition of Home Food Preservation is becoming popular once again. I wanted to share some of the questions and answers with you:

Can food be re-canned if the lid does not seal? Canned food can safely be recanned if the unsealed jar is discovered within 24 hours. To re-can, remove the lid and check the jar sealing surface for tiny nicks. Change the jar; if necessary, adding a new treated lid and reprocess using the same processing time.

If my recipe doesn’t call for processing, do I need to do so? Many recipes passed down through the years or found in older cookbooks do not include instructions for processing. The foods are usually canned by the open kettle method, sealed and stored. Foods prepared in this manner present a serious health risk — particularly low-acid foods. To minimize the risk of food spoilage, all high-acid foods should be processed in a water bath canner or pressure canner and all low-acid foods in a pressure canner.

Do I really need to leave a certain amount of headspace in the jar? Yes, leaving the specified amount of headspace in a jar is important to assure a vacuum seal. If too little headspace is allowed the food may expand and bubble out when air is being forced out from under the lid during the processing. The bubbling food may leave a deposit on the rim of the jar or the seal of the lid and prevent the jar from sealing properly. If too much headspace is allowed, the food at the top is likely to discolor. Also, the jar may not seal properly because there will not be enough processing time to drive all the air out of the jar.

How long will canned food keep? Properly canned food stored in a cool, dry place will retain optimum eating quality for at least one year. Canned food stored in a warm place near hot pipes, a range, a furnace or in indirect sunlight may lose some of its eating quality in a few weeks or months, depending on the temperature. Dampness may corrode cans or metal lids and cause leakage so the food will spoil.

Is it safe to process food in the oven? NO. This can be dangerous because the temperature will vary according to the accuracy of oven regulators and circulation of heat. Dry heat is very slow in penetrating into jars of food. Also, jars explode easily in the oven.

Is it all right to reuse jar fittings (lids and bands)? Lids should not be used a second time since the sealing compound becomes indented by the first use, preventing another airtight seal. Screw bands may be reused unless they are badly rusted or the top edge is pried up which would prevent a proper seal.

If I find mold growing inside a jar of canned food, can I just scrape it off and eat the food? Mold growth in foods can raise the ph of the food. In home canned products, this could mean that the high-acid products could become low-acid and therefore run the risk of botulism or other bacterial spoilage. Thus, any home canned produce that shows signs of mold growth should be discarded. The exception to this is jellied products. In these the high-sugar content would prevent the growth of clostridium botulinum.

Why do the undersides of metal lids sometimes discolor? Natural compounds in some foods, particularly acids, corrode metal and make a dark deposit on the underside of jar lids. This deposit on lids of sealed, properly processed canned foods is harmless.

How can I remove scale or hard-water film from canning jars? Soak jars for several hours in a solution containing one cup of vinegar and one gallon of water.

These were just several of the general questions that have come into the office — if you have others, just give us a call. Of course, what better place to get your vegetables for canning than the Downtown Farmers Market? Just enjoy!

Joan Mason is Sumter County Extension agent/Family & Consumer Sciences, University of Georgia Cooperative Extension Service. Contact her at 924-4476.