Botulism, A canning risk easily avoided.

Botulism: A severe, sometimes fatal food poisoning caused by ingestion of food containing botulin and characterized by nausea, vomiting, disturbed vision, muscular weakness, and fatigue. Symptoms also include difficulty in swallowing, speech and breathing.

Doesn’t sound like anything I want to mess around with!

Chlostridium Botulinum Did you know that Chlostridium Botulinum spores are on most fresh food surfaces?  It is in the dirt, it is just about everywhere.  

The spores are harmless on fresh foods. However, when certain conditions exist, these spores will germinate, multiply, begin dying, and then produce a deadly toxin. It is this toxin that causes serious food poisoning.   

So how do we get rid of it???  Heat.

The conditions where the spores become dangerous are:

  • absence of oxygen,
  • low acidity levels, and
  • temperatures between 40 and 120 degrees Fahrenheit (4.5 to 49 degrees Celsius)—

Sounds just like the conditions in canned foods!  Both home canned or commercially canned.

Botulism spores are killed at temperatures above 240 degrees Farenhieght .  This is only achievable in a pressure canner.  

As a home canner, If you follow the recommended guidelines, and process your foods with the correct canning methods you should have no problems.

Added Precaution

As an added precaution it is suggested that you boil low acid foods for 10 minutes before serving. This includes all vegetables and meats.  

There is apparently some debate even among extension services about whether this is a necessary step. If you have questions about the importance of boiling your low acids, call your local extension service and ask for more details.    

After talking with my local extension service , I have decided that the extra step is not that much work and it gives me peace of mind and so I do it.  I'd recommend the same for you.  You'll have to decide.

Boil for 10 minutes, plus one minute per 1,000 feet above sea level.  Home canned spinach and corn should be boiled for 20 minutes before eating.

This is especially important at higher altitudes and in the Western United States. According to my local extension service, soil in the area from the Rocky Mountains to the Pacific Ocean contains higher rates of Type A Chlostridium Botulinum.  

More Canning Safety Articles

Canning Methods - which one to choose?
Step by step: Pressure Canning
Step by Step: Water Bath Canning
Tomatoes Safety
Unsafe Methods
Spoiled Food
Altitude Adjustments
Botulism
Sterilizing Canning Jars
Canning Terms


Canning Books by Sharon

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