Nothing beats fresh produce in season, whether you pick it from your own garden or orchard, or you buy it from a local produce market. It makes sense to take advantage of the flavor and nutrition value of the many fruits and vegetables available. Fresh produce is the most economical when it is in season as well.
Throughout history people have preserved produce in times of plenty in order to have food during the winter. Today we don't have to preserve food for winter; because it is readily available at our local grocery store year round. However, many people still preserve foods through canning, freezing, and drying methods. The reasons are somewhat different today than in the past. While it isn't a necessity to preserve food, many people enjoy making specialty products, or they enjoy gardening and want to utilize the bounty that results from their efforts. Some people prefer the flavor and quality of their own home preserved products. They enjoy the control they have over what is put into their foods. Also, if you don't include the cost of your time, home preserved foods can be less expensive than purchased foods.
While home food preservation has a long history, there are many procedures that were used in the past that more recent research reveals are not safe. It is not worth the time and effort to grow produce or the money to buy fresh produce to preserve and risk having it spoil or make someone ill because you are using out dated recipes or methods. Grandma's old recipe for pickles, tomato sauce, peppers, or other products might not be a lab tested recipe and might not be safe.
Safety with home food preservation is a serious matter. You want to control spoilage but you also want foods to be safe to eat. There are some microorganisms that cause spoilage and others that cause foods to be unsafe, even though the food may look and smell perfectly okay. In food preservation, you want to control both spoilage and pathogenic microorganisms.
Canning is a food preservation method where many people are using outdated methods or procedures. The key to what is determined safe for canning is based on heating food to a high enough temperature to destroy both spoilage and pathogenic microorganisms. Clostridium botulinum, which can cause the potentially deadly illness Botulism, is the most heat resistant pathogenic microorganism. The recommendations are based on destroying or controlling this bacteria, knowing that other pathogenic microorganisms will also be destroyed or controlled with these procedures. Each food product is different in the way heat penetrates the food and so processing times vary depending on how long it takes each food to reach the proper temperature in the center of the jar. This is all done under controlled conditions in a laboratory to develop the current USDA recommendations. This is not what happened in grandma's or in her mom's kitchen when her canning recipes were developed.
Acidity plays an important role in canning as a food preservation method. Acid will inhibit the growth of pathogenic bacteria like Clostridium botulinum. Therefore, acid foods like fruits and pickles can be processed using a boiling water bath method. In a boiling water bath the temperature only reaches 212 degrees which will not destroy Clostridium botulinum, however the acid in the food will control the growth of this bacteria.
Tomatoes and tomato products can also be processed with a boiling water bath if they are acidified. USDA recommends the addition of citric acid (1/2 teaspoon) or bottled lemon juice (2 tablespoons) per quart to all tomato products to boost acidity when canning.
Low acid foods, including all vegetables and meats, must be processed under pressure using a pressure canner. Without the acid to control the growth of Clostridium botulinum, this bacteria must be destroyed to ensure the food is safe. The only way to destroy Clostridium botulinum is under pressure where the temperature can get up to 240 degrees. Processing these products in a boiling water bath is like playing roulette. There is no way the Clostridium botulinum, if present will be destroyed.
All foods must be processed by one of these approved methods, boiling water bath or under pressure, to be safe. Open kettle canning where hot food is place in a hot jar, the lid put on, and not further processing takes place is not safe. Processing destroys pathogens but it also serves some other very important purposes. It drives air out of the jars to create a true vacuum inside the jar and it sterilizes the product inside a closed environment (inside the jar) which, if the jar seals properly, cannot become contaminated until the jar is opened. With open kettle canning, you do not have a sterile environment inside the jar and you do not have a true vacuum. There is air in the head space at the top of the jar.
It is also important to make sure your equipment, particularly your pressure canner is working properly. The dial gauges on pressure canners can become inaccurate over time. They can be tested for accuracy by Ohio State University Extension for $5. Call (419) 668-8219 for details. USDA recommends that this test be done annually. The weighted or giggle style pressure regulators do not need to be tested.
So, where do you get up-to-date instructions for home food preservation? The Ohio State University Extension Service can provide the most recent USDA procedures, recipes and instructions. You can also call the OSU Extension Office at (419) 668-8219 with questions. Factsheets with basic food preservation information are available from the OSU Extension Office or on Ohioline at http://ohioline.osu.edu. The USDA Complete Guide to Home Canning is available at the OSU Extension Office for $5. This book includes more in-depth information than the fact sheets and more recipes. You can also find this resource online from the National Center for Home Food Preservation (NCHFP) atwww.uga.edu/nchfp. Clink on Publications once you are on this site. The NCHFP also features a wealth of other information and resources as well, including So Easy to Preserve. This book, developed by the University of Georgia Extension, has just been updated and includes the latest USDA recommendations for safe food preservation, including canning, freezing, and drying. A self study titled Preserving Food at Home is also available on the NCHFP web site.
Safe home food preservation is not a simple process of doing what has been done in the past. It is a great way to preserve the harvest bounty from your garden but it is not worth the risk to use outdated procedures. It is a much more involved process that can not be adequately covered in a newspaper article. It is essential that people seek out the most up-to-date resources available on this topic.
Deb Angell is the Family and Consumer Sciences Extension Educator for Huron County's Ohio State University Extension Office, 180 Milan Ave., Suite 1 Norwalk, OH 44857. She can be reached by phone at (419) 668-8219 or via e-mail at firstname.lastname@example.org.