Several methods to preserve food; explore your options (with salsa recipe)

Any food will spoil over time unless preservation steps are taken.

Preserved food lasts longer than fresh produce and refrigerated items. Decide what you are preserving. The answer will help determine what method to use. Here are the most common ways.


Freezing food is an easy and quick method. Proper freezing of fruits and vegetables tends to maintain their color, flavor, and nutrients better than other methods.


Pickling uses a high concentration of acid to prevent spoilage. Pickled foods are saturated with acid to smother most bacteria. Heat treating these products is also important to kill any remaining bacteria in a jar.


Fermenting is done in a warm environment using salts, sugars, or grains creating a brine, which covers the produce. Time is an important factor when fermenting.

Water Bath Canning

Water bath canning is used for high-acid foods and recipes that incorporate the correct amount of acid. The combination of time and temperature destroys mold, yeast, and enzymes that cause spoilage while creating a vacuum-sealed jar. This process is recommended for produce and recipes including most fruits and acidified and fermented foods.

Pressure Canning

Pressure canning is the only processing method that reaches the 240°F temperature needed to safely preserve low-acid foods. Time and temperature will destroy foodborne bacteria and create a vacuum-sealed jar necessary to prevent spoilage. This process is required to preserve meats, most vegetables, and combination foods.

Pressure canner dial gauges should be tested for accuracy each year. Contact your local University of Wyoming Extension office to determine locations and times for testing.


Dehydration prevents and delays spoilage by removing most of the food’s water content. While possible to dry most fruits and vegetables in an oven or even in the sun, you’ll get more dependable results using an electric dehydrator.

Use Current Methods and Recipes

Significant changes to canning guidelines were made in 1994, 2006, 2009, and again in 2015. Botulism can’t be seen, smelled, or tasted, so the best way to prevent foodborne illness is to only use recipes that have been tested by reliable sources and have a known pH. ALWAYS use current research-based recipes developed after 2009 and preferably 2015.

Preserving some foods during their most abundant time is one of the best ways to eat a local, seasonal diet year-round. Contact your local UW Extension office for complete details on food preservation and upcoming classes. Contact information is at

UW Extension recommends using one of the following approved resources for home canning recipes.


  • Ball Blue Book cookbooks
  • So Easy to Preserve, 6th Edition, 2014
  • USDA Complete Guide to Home Canning, Revised 2015


Vicki Hayman is a University of Wyoming Extension nutrition and food safety educator. She can be reached at (307) 746-3531 or at

Fresh Vegetable Salsa

Makes about 10 (8 oz.) half pints or 5 (16 oz.) pints


  • 7 cups (8-10 medium-large) tomatoes
  • 8 jalapeño peppers, seeded and finely chopped
  • 2 cups onions, coarsely chopped
  • 1 cup green bell pepper, coarsely chopped
  • 3 cloves garlic, minced
  • 1 can (6 oz.) tomato paste
  • 3/4 cup white vinegar
  • 1/2 cup chopped cilantro, lightly packed
  • 1/2 teaspoon ground cumin
  • 10 (8 oz.) half-pint or 5 (16 oz.) pint preserving jars with lids and bands


  • Blanch, peel, seed, and coarsely chop tomatoes. Measure 7 cups. Wearing rubber gloves, remove seeds, and finely chop jalapeño.
  • In a large stainless-steel saucepan, combine tomatoes, jalapeño pepper, onions, green pepper, garlic, tomato paste, vinegar, cilantro, and cumin. Bring to a boil; boil gently, stirring occasionally, until salsa thickens, about 30 minutes.
  • Fill canner halfway with hot water, cover, and pre-heat to 180°F (simmering) for hot pack.
  • Heat canning jars in hot water until ready for use; however, do not boil!
  • Place flat lids in a small saucepan and bring to a simmer over low heat until ready to use – do not boil. Set bands aside.
  • Ladle salsa into hot jars one at a time, leaving a ½-inch headspace. Adjust headspace if necessary.
  • Remove air bubbles with a straight spatula. Wipe jar rim/threads using a clean damp cloth/paper towel to remove any food residue. Center the lid on jar. Screw on band until fit is “fingertip” tight.
  • Place jars in canner rack and lower rack into water. Make sure 1-2 inches of water covers jar; add more hot water if necessary.
  • Place lid on the canner and bring to a full rolling boil. Once at a rolling boil, set timer and begin processing time. Process in a boiling water canner for the appropriate time according to the altitude chart.
  • Once processing time is complete, turn off the heat, remove the canner lid, and wait 5 minutes before removing jars.
  • Remove jars from canner without tilting and set upright on a towel with 1-inch space between jars to prevent jar breakage. Leave jars undisturbed for 24 hours. Do not re-tighten bands or push on the center of lids!
  • Check the jar lids for a good seal after 24 hours. The lid should not flex up and down when the center is pressed. If it does, refrigerate the jar and use food within two days.
  • Remove bands. Clean the jars, label, and store in a cool, dry, dark place. Consume within one year for best quality.

Tips: When cutting or seeding hot peppers, wear rubber gloves to keep hands from burning. If you don’t mind heat, leave the seeds and veins in the jalapeños.

Recipe source: Ball Complete Book of Home Preserving

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