Canning Vegetables Safely

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    06-Jan-2016

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Canning Vegetables Safely. Resources for Today. Canning Vegetables Safely (B1159) Using and Caring for a Pressure Canner (B2593). Canning Vegetables Safely. Low-acid foods must be pressure canned High temperatures destroy botulinum spores. A look at Botulism Poisoning. - PowerPoint PPT Presentation

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<ul><li><p>Canning Vegetables Safely </p></li><li><p>Resources for TodayCanning Vegetables Safely (B1159)Using and Caring for a Pressure Canner (B2593)</p></li><li><p>Canning Vegetables Safely</p><p>Low-acid foods must be pressure cannedHigh temperatures destroy botulinum spores </p></li><li><p>A look at Botulism PoisoningSpores of Clostridium botulinum are in the soil Toxin production requires: low acid (pH&gt;4.6), no oxygen, warm temperatures </p></li><li><p>Processing of Low-Acid FoodHigh pressureHigh temperatureShorter processing timeHigher quality</p></li><li><p>Question time??</p></li><li><p>A Pressure Canning Checklist:Check gauges, vent ports, gaskets Check canning jarsPreheat jars and pre-treat lidsFollow instructions EXACTLY for jar size, pack, and fill</p></li><li><p>Packing Jars for Pressure ProcessingGreen Beans-RAW packWash and trim. Pack raw beans tightly into hot jars, leaving 1-inch headspace. Add salt. Cover with boiling water, leaving 1-inch headspace. Remove air bubbles. Wipe jar rims. Adjust lids and process at 11 psi. Pints 20 min.; Quarts 25 min.</p><p>Green Beans-HOT packWash and trim. Heat beans for 5 minutes in boiling water. Pack hot beans into hot jars, leaving 1-inch headspace. Add salt. Cover with boiling cooking liquid, leaving 1-inch headspace. Remove air bubbles. Wipe jar rims. Adjust lids and process at 11 psi. Pints 20 min.; Quarts 25 min. </p></li><li><p>Processing in a Pressure CannerPlace filled jars on a rack in 2-3 inches of simmering waterFasten canner lid and vent 10 min.Adjust pressure for elevationStart counting time once pressure is reachedWhen time is up, allow pressure to drop on its own</p></li><li><p>Processing in a Pressure CannerPlace filled jars on a rack in 2-3 inches of simmering waterFasten canner lid and vent 10 min.Adjust pressure for elevationStart counting time once pressure is reachedWhen time is up, allow pressure to drop on its own</p></li><li><p>After ProcessingRemove jars from canner and allow to coolDo NOT tighten screw bandsCheck seals of cooled jarsLabel, date and store</p></li><li><p>Canning VegetablesSelect high quality vegetablesWash all veggies &amp; peel and/or blanch if requiredAdjust seasoning as desired </p></li><li><p>More Hints for Canning Vegetables SafelyDo not thickenDo not adapt jar sizesCanning mixturesAdjust for altitude</p></li><li><p>Question time??</p></li><li><p>What if. Jars fail to sealToo much liquid is lost.You need to reprocessThe canner seals shut.You dont know if its safe</p></li><li><p>What if. Jars fail to sealToo much liquid is lost.You need to reprocessThe canner seals shut.You dont know if its safe</p></li><li><p>Question time??</p></li><li><p>How Long Does It Keep?Canned vegetables and meat: 1 year under proper storage conditions</p><p>*Welcome to our series of Wisline programs on home food preservation. Today we will talk about the basics of canning vegetables safely. Canning vegetables is not only fun to do, but what could be more delicious than winter-time meals prepared with vegetables preserved from your summer garden. Add home-canned meat to those vegetables, and you have a hearty stew prepared from items on your pantry shelf. </p><p>Before we get started, lets see who is joining us today. (Roll call)</p><p>Thanks to everyone for joining us today. Lets get started. </p><p>*Many of the points in todays discussion come from our UWEX publication:B1159 Canning Vegetables Safely</p><p>Another good resource is B2593 Using and Caring for a Pressure Canner. Both of these resources are available online: http://cecommerce.uwex.edu/</p><p>*It wont be long before gardeners will be harvesting a bounty of green peas, carrots and corn. And fresh green peas are already a part of many family dinners. </p><p>Canning low-acid foods like meat, wild game, fish, poultry and vegetables requires special care. Low-acid foods can support the production of the deadly botulism toxin if these foods are not properly processed in a pressure canner. A pressure canner heats food to high temperatures, 240 to 250F or higher, and destroys the spores that produce botulism toxin. A boiling water canner such as might be used for canning pickles or fruit heats food only to 212F, not high enough to ensure safety while maintaining quality.</p><p>*The spores of the bacterium Clostridium botulinum are naturally present in the environment, and notably in soil. These spores are very heat resistant and will survive boiling in water for hours. Under conditions of low acid, no air, and warm temperatures, the spores of C. botulinum can germinate (sort of like seeds growing), and as they germinate they produce the deadly botulism toxin. This toxin is one of the most deadly poisons known; even a small amount can kill a human. So, when we can low acid foods like vegetables and meats, we must destroy botulinum spores so that they do not germinate in the jar and produce the poison.</p><p>*Remember back to FAT TOM and the relationship between time and temperature? In water bath canning, jars are heated in boiling water at 212F and held in the boiling water for enough time to ensure a seal and destroy some microorganisms. But the spores of Clostridium botulinum are very heat resistant and would not be destroyed unless food was boiled for a long period of time. So, we use high pressure to create higher temperatures. With higher temperatures we can heat process for a relatively short period of time and still destroy the deadly botulinum spores. The result is a product that is safe, but still of high quality.</p><p> In pressure canning, water is heated in the canner and turns to steam at 212. In a closed vessel like a sealed canner, the steam will eventually create pressure. This increased pressure forces water to boil at a higher temperature, i.e. 240F - 250F, and destroys heat-tolerant microbes. </p><p>PV=nRT*Let me take a minute to ask is there are any questions that you have at this point.*It is very important that you carefully follow instructions for pressure canning. At least once each season check dial gauges for calibration; at each canning session take a moment to check vest ports and gaskets. Use standard home canning jars that are free of chips and cracks. Do not use mayonnaise jars or other commercial jars for pressure canning; these jars may be acceptable for water bath canning if they will accept a standard 2-piece lid.Preheat jars and pre-treat lids. Jars can be filled by the Hot Pack or the Raw Pack method. Regardless, jars need to be preheated to avoid thermal stress on the jars as they are filled with hot liquid.Follow research-tested recipes exactly for jar size, type of pack (hot or raw), whether jars are to be loosely or tightly filled, etc. Failure to follow directions exactly may result in canning an unsafe product. *Jars can be hot-packed or raw-packed, depending on what the recipe calls for; sometimes there is a choice. For instance, green beans can be hot or raw packed. The differences in the 2 recipes are highlighted.Here are some things to note:Raw Pack means that the food is placed in the jars without prior cooking, but the liquid added to the jars still must be hot/boiling. When researchers establish safe canning processes, the heat of the food/liquid in the jar is part of the thermal process. Hot Pack means that the food is heated in liquid prior to being packed into jars. The advantage of the hot pack method is that you can pack more food into a given jar since some of the air is expelled from the product on heating. When canning meat, the quality if often superior with hot pack. In this case, the processing time is the same for hot and raw pack. In each case, leave the appropriate head space. Head space is the space between the top of the jar rim and the level of liquid/food in the jar. Removing air bubbles, along with wiping jar rims, helps to ensure a good seal. The flat lids must be pre-treated according to the manufacturers instructions. Adjust lids so that they are FINGER TIGHT. Do not fully tighten the lids, as the air in the jars needs to escape during process so that a vacuum can form.Both time and pressure are specified for each process.</p><p>*When you are ready to process vegetables or meat in a pressure canner, start by placing 2-3 inches of simmering water in the bottom of the canner. Make sure the canner has a rack in the bottom so that jars can rest above the bottom of the canner. A very few recipes call for more than 2-3 inches of water in the canner, so be sure to follow recipe instructions exactly. </p><p>Set filled jars on a rack in the canner so steam can flow freely around each jar. </p><p>Fill the canner with the appropriate size jar (most often pints and quarts). A double layer of jars may be used as long as there is a rack placed between the layers; rest the upper layer of jars on the rims of the bottom layer, not on the lids. You can mix pints and quarts if the processing time is the same. If the time is not the same, then the contents of the jars with the shorter processing time will be over-processed, but safe to consume.</p><p>Fasten the canner lid in place and heat over high heat. The canner MUST be vented for 10 minutes to drive air from the canner. This is often a problem for novice canners- they are frustrated because it takes for ever for their canner to pressurize but this is because they have forgotten to vent the canner. Be sure to select the appropriate canning pressure based on the elevation where you live. Water will boil at different temperatures based on elevation above sea level. At higher elevations, the atmospheric pressure is lower and the temperature at which water boils is lower; so here pressure must be higher to produce the needed high temperatures for canning. Start timing the venting process once a steady stream of steam is seen exiting from the vent port. After steam flows for 10 minutes, close the petcock or place the pressure regulator on the vent pipe and let the pressure rise to the appropriate level. </p><p>Start counting the timing process when the correct pressure is reached. For Dial gauge canners, the pressure will be registered on the gauge; for Weighted gauge canners, there will be a rocking or jiggling of the weight which will indicate that pressure is reached. (Follow the manufacturers instructions.) Maintain the pressure at a steady level by regulating the heat under the canner. Fluctuating pressure can cause jars to lose liquid and damage the seals, or lead to under-processing or unsafe food. If at any time during the process the pressure drops below the level for safe processing, bring the pressure back up and retime for THE ENTIRE PROCESSING PERIOD.When the process time is up, turn off the heat and remove the canner from the burner, if possible. Let the pressure drop on its own. Do NOT force-cool the canner. Force-cooling with cold water will cause the jars to lose liquid and may damage their seals and will also lead to under-processing and an unsafe product.*Start timing the venting process once a steady stream of steam is seen exiting from the vent port. After steam flows for 10 minutes, close the petcock or place the pressure regulator on the vent pipe and let the pressure rise to the appropriate level. </p><p>Start counting the timing process when the correct pressure is reached. For Dial gauge canners, the pressure will be registered on the gauge; for Weighted gauge canners, there will be a rocking or jiggling of the weight which will indicate that pressure is reached. (Follow the manufacturers instructions.) Maintain the pressure at a steady level by regulating the heat under the canner. Fluctuating pressure can cause jars to lose liquid and damage the seals, or lead to under-processing or unsafe food. If at any time during the process the pressure drops below the level for safe processing, bring the pressure back up and retime for THE ENTIRE PROCESSING PERIOD.When the process time is up, turn off the heat and remove the canner from the burner, if possible. Let the pressure drop on its own. Do NOT force-cool the canner. Force-cooling with cold water will cause the jars to lose liquid and may damage their seals and will also lead to under-processing and an unsafe product.*Remove jars from the canner and place them upright on a towel or rack away from drafts to cool. Do not retighten the screw band. If some liquid has boiled out during processing, do not open the jar to add more. If only a small amount of liquid boils out (less than half) and the lid seals properly, the food will be safe to eat. However, food that is not covered with liquid may darken during storage. If more than half the liquid has been lost, either reprocess the vegetables with added liquid, or freeze the contents of these jars. Liquid is necessary for adequate heat penetration. Losing too much liquid during processing can lead to under-processing and an unsafe food can result.After the jars have cooled completely, check the seals. Press the center of flat metal lids. If the lid is down and does not move, the jar is sealed. After 24 hours, you can remove metal bands, wash and store them for re-use.Wipe sealed jars clean, label and date. For optimum quality, use home-canned food within one year. Properly home-canned food will remain safe for years, but quality will suffer on extended storage. Store jars in a cool, dry place to retain the best eating quality and protect the lids from rusting. </p><p>*Select high quality vegetables for canning. Canning will not improve the quality of any item. Discard rotten or severely damaged produce. Make sure that the type of vegetable is compatible with the high heat of the canning process. Some vegetables such as broccoli, cabbage, cauliflower and summer squash are not recommended for home canning. This may be due to quality considerations (broccoli and cabbage) or because safe canning recommendations have not been developed (summer squash). Carefully wash all vegetables for canning to remove soil and bacteria that might be present.Peel or slice as desired. Note, follow recipe directions precisely, i.e. instructions for canning potatoes require that these be peeled. Some vegetables, such as spinach should be blanched before canning.Salt is added to canned food for flavor, and can easily be omitted. A small amount of herbs can be added to each jar for flavor as the heat process will be sufficient to accommodate this.*Do not thicken, or add rice, barley or pasta to vegetables. These starchy ingredients absorb liquid during processing, and change the heat transfer characteristics of the product. Under-processing could result.Do not adapt recipes for jar sizes that are not listed in the recipe. An unsafe product may result. For instance, safe canning recommendations for cream style corn in quart jars are NOT available; can this mixture in pints only.When you can a combination of vegetables, check the processing time for each vegetable and use the longest time. Product quality will be better if processing times are similar for the vegetables you combine. For example, if corn is included in a mixture, the processing time is going to be very long and will greatly overcook vegetables like green beans, carrots, or peas that have shorter process times.Wisconsin elevations range from 580 to 1,953 feet above sea level. Using the pr...</p></li></ul>