Common food preservation mistakes: An eight question quiz on canning safely

Take this eight question quiz to see what you know about canning food safely.

Some home canners may be tempted to create or alter food preservation recipes, but Michigan State University (MSU) Extension educators urge following tested and recommended recipes carefully to avoid food-borne illness.

The following eight-question quiz was written by MSU Extension educator Rita Klavinski so consumers could test their knowledge of safe canning methods.

Do you:

  1. Make up your own canning recipes?
    Without using scientifically tested recipes and methods, you will not know how long the products need to be processed to be safe. Visit the National Center for Home Food Preservation for scientifically tested recipes.
  2. Add extra starch, flour or other thickener to your recipe?
    Adding thickeners changes the rate of heat penetration into the product and can result in underprocessing. This might make the product unsafe to eat.
  3. Add extra onions, chilies, bell peppers or other vegetables to salsa?
    Extra vegetables added to salsa mixtures can dilute the acidity enough that Clostridium botulinum, the microorganism that causes botulism, a deadly disease associated with improper canning, can grow in the product.
  4. Use your oven instead of a boiling water bath to process high-acid foods?
    This is a huge food safety risk and a physical safety risk. Never can food in your oven – the jars might blow up.
  5. Skip the venting step?
    Not venting the pressure canner before processing can result in air pockets that will not reach the high temperature needed to process foods properly.
  6. Fail to add acid to home-canned tomatoes?
    Not acidifying tomatoes may result in a product that could support the growth of botulism-causing bacteria. Use 1 tablespoon of lemon juice per pint or 2 tablespoons per quart. Or you may choose to use ¼ teaspoon citric acid per pint and ½ teaspoon per quart.
  7. Cool your pressure canner under running water?
    Research-based calculations for processing times include the residual heat during the normal cool-down period as part of the heating process. Hurrying this process will result in underprocessed food that might be unsafe to eat.
  8. Retighten screw bands while the jars are still hot?
    Do not retighten screw bands. Retightening the bands may interfere with the sealing process.

Improve the safety and quality of your home-canned foods by processing your food correctly. Michigan State University (MSU) Extension has developed a Preserving Food Safely DVD that is available through the MSU Extension Bookstore.

The Michigan Fresh website also offers fact sheets on storage and preserving techniques for fruits and vegetables.

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