| FOOD PRESERVATION/CANNING |
| Canning is an important, safe method for preserving food if practiced properly. The canning process involves placing foods in jars or similar containers and heating them to a temperature that destroys micro-organisms that cause food to spoil. During this heating process air is driven out of the jar and as it cools a vacuum seal is formed. This vacuum seal prevents air from getting back into the product bringing with it contaminating micro-organisms. There are two safe ways of processing food, the boiling water bath method and the pressure canner method: The boiling water bath method is safe for tomatoes, fruits, jams, jellies, pickles and other preserves. In this method, jars of food are heated completely covered with boiling water (212�F at sea level) and cooked for a specified amount of time Pressure canning is the only safe method of preserving vegetables, meats, poultry and seafood. Jars of food are placed in 2 to 3 inches of water in a special pressure cooker which is heated to a temperature of at least 240� F. This temperature can only be reached using the pressure method. A microorganism called Clostridium botulinum is the main reason why pressure processing is necessary. Though the bacterial cells are killed at boiling temperatures, they can form spores that can withstand these temperatures. The spores grow well in low acid foods, in the absence of air, such as in canned low acidic foods like meats and vegetables. When the spores begin to grow, they produce the deadly botulinum toxins(poisons). The only way to destroy these spores is by pressure cooking the food at a temperature of 240�F, or above, for a specified amount of time depending on the type of food and altitude. Foods that are low acid have a pH of more than 4.6 and because of the danger of botulism, they must be prepared in a pressure canner. The low acidic foods include: *meats *poultry *dairy products *all vegetables High acid foods have a pH of 4.6 or less and contain enough acid so that the Clostridium botulinum spores can not grow and produce their deadly toxin. High acidic foods can be safely canned using the boiling water bath method. The high acidic foods include: *fruits *properly pickled vegetables Certain foods like, tomatoes and figs, that have a pH value close to 4.6 need to have acid added to them in order to use the water bath method. This is accomplished by adding lemon juice of citric acid. Processing Methods Boiling Water Bath Fill the kettle with the appropriate amount of hot water and begin heating it on the range. The water bath canner requires 1 to 2 inches of water above the tops of jars. This can be difficult to determine before the filled jars are in place but after a batch or two you will learn how much water you you have to add. It is always a good idea to have an extra small pot of water heating just in case. Place jars on rack immediately after packing. Lower filled rack into canner. Jars should be covered by 1 to 2 inches of water. Add additional boiling water if needed. If you add more water, pour between jars and not directly on them (this is where the extra pot of heated water comes in handy). Cover pot with lid. When the water comes to a rolling boil, start to count the processing time. Reduce heat slightly and boil gently for the time recommended for the food being processed. When the cooking time is up, remove jars at once and place on a rack or on towels away from heat and away from any draft. Keep jars separated to allow for air space. After jars have cooled, test for seal. To do this press down on the center of the lid. The lid should be con-caved and not move when pressed. Another method is to tap the lid with the bottom of a teaspoon. If the jar is sealed correctly, it will make a high-pitched sound. If it makes a dull sound it means the lid is not sealed or possibly that food is in contact with the underside of the lid. When completely cool, the screw bands may be removed if desired but not necessary. Be sure to label canned jars with content and processing date. Store jars in a cool dark, dry place. If there is a possibility of freezing temperatures during storage, cover with a blanket or heavy cloth. Jars may also be placed in a box and stuffed with newspaper. Pressure Canner Follow manufactures instructions for opening and closing the pressure canner. Have 2 to 3 inches of hot water in pressure canner and stand the jars on the rack insert so they are not touching each other or the sides of the pot. Fasten lid and turn on heat. Steam, mixed with air, will start to flow from the vent and then This is about 8 to 10 minutes after the first sign of steam. As the air is driven out from the canner the steam will change from a white vapor or cloud to nearly invisible. Start processing time when pressure has been reached or when weighted gauge begins to rock. It is then time to close the the pet-cock or regulator. Maintain a steady pressure during processing. When processing time is up, remove the canner from heat and let the pressure return to zero without assistance. Standard heavy-walled canners take about 30 minutes when loaded with pints and about 45 minutes when loaded with quarts. Do not attempt to cool pot with cold water. This can cause liquid to escape from jars and keep lids from properly sealing. It can also cause pot warpage. After pressure reaches zero, wait 2 minutes longer and then slowly open or remove the pet-cock or regulator. Unfasten cover and tilt the far side up so any steam remaining will escape away from you. Using a jar lifter, remove each jar and place on a dry, non-metallic surface or towel. Leave space between jars for air circulation. After jars have cooled, test for seal and the screw bands may be removed if desired. Be sure to label canned jars with content and processing date. Store jars in a cool dark, dry place. |
| Now that we have understood all about food preservation/canning, we are ready to make our own. Click below for some zesty canning recipes: |