Food Safety Facts for Canning

Changing the makeup of a canning recipes can be harmful to your health and even deadly. Recipe alterations can also be costly in time, produce and money. You should only use scientific tested recipes for home canning and USDA recommended procedures. Below are a few major canning problems.

Potentially Deadly

What	Why It Is Unsafe
Making up own canning recipes.	Without scientific testing, you will not know how long the product needs to be processed to be safe.
Adding extra starch, flour or other thickener to recipe.	This will change the rate of heat penetration into the product and can result in under cooking.
Adding extra onions, chili, bell pepper or other vegetables to salsas.	The extra vegetable dilute the acidity and can result in botulism poisoning.
Using oven instead of water bath for processing.	The product will be under processed since air is not as good a conductor of heat as water or steam. The jars also may blow up.
Not making altitude adjustments.	Since boiling temperatures are lower at higher altitudes, the products will be undercooked.
Not venting pressure cooker first.	Lack of venting can result in air pockets which will not reach as high a temperatures.
Not having gauge pressure canners tested annually.	If the gauge is inaccurate, the food may be under processed.
Failure to acidify canned tomatoes.	Not all tomatoes have an adequate acid level, especially if the vine is dead. This can result in botulism poisoning.
Letting food cool before processing in the recipes that call for "hot pack."	The heat curves are based on the food being hot at the beginning of the processing. Product could be under processed.
Cooling pressure canner under running water.	Calculations as to cooking time includes the residual heat during the normal cool-down period as par of the heat process. Hurrying this process will result in under processed food.

Please Note: Canned meat, vegetables or salsa which were under-processed can cause botulism.

Other Possible Hazardous, Maybe Deadly but Mostly Economic Loss

What	Why It Is Unsafe
Use of mayonnaise jars.	The jar may blow-up, especially if used in a pressure canner, and it may be more difficult to obtain a good seal. However, if it seals, it is safe to use.
Use of paraffin on jams and preserves.	Small air holes in the paraffin may allow mold to grow. Also paraffin can catch on fire if overheated. If it has mold growth, throw out the product.
Cooling too slowly after removing from canner. (Example: stacked jars close together.)	There are a group of harmless organisms called thermophiles which can survive on canning. If bottles are held hot for long periods, they can produce acid. This results in the defect known as "flat-sour.' Harmless, but very undesirable flavor.
Storing food longer than recommended.	Lengthy or overly hot storage will decrease quality and some nutrients but the product wills till be safe to eat.

Never change anything in canning recipe except these exceptions. Feel free to:

1. Change salt level in anything except pickles.
2. Change sugar level in syrup used for canned fruit.
3. Add extra vinegar or lemon juice.
4. Decrease any vegetables except tomatoes in salsas.
5. Substitute bell pepper, long green peppers or jalapeno peppers for each other in salsa recipes as long as you do not increase the total amount.

General Rules

1. Always exactly follow a scientifically tested recipe. (Exceptions listed above.)
2. Make altitude adjustments by adding more time to water bath canning or increasing pressure for pressured canned products.
3. Unless you are sure that everything was perfect in the processing, boil the product for 10 minutes before eating.

This information supplied by the Utah State University Extension, reference FN-250.7