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Farm to Table: Is home canning safe?

Contributed by Teri Gregg

Home canning

Are home-canned products safe to eat?

Is it safe to eat Aunt Gab’s or Grandma Mary’s pickles, green beans and preserves?  Every year, people proudly give their homemade canned goods for gifts and the wary recipients leave them in their cupboard for years wondering if they are really safe to eat. If this sounds like you, then here is some helpful information to help you decide when to toss a canned good and when to sing Aunt Gab’s and Grandma Mary’s praises!

What is canning?

Canning is a method of preserving food in which the food contents are processed and sealed in an airtight container. Canning provides a shelf life typically ranging from one to five years, In 1795 the French military offered a cash prize of 12,000 francs for a new method to preserve food. Nicolas Alpert  suggested canning, and the process was first proven in 1806 in tests conducted by the French navy.  The packaging prevents microorganisms from entering and proliferating inside.

To prevent the food from being spoiled before and during containment, a number of methods are used: pasteurisation, boiling (and other applications of high temperature over a period of time), refrigeration, freezing, drying, vacuum treatment, antimicrobial agents that are natural to the recipe of the foods being preserved, a sufficient dose of ionizing radiation, submersion in a strong saline solution, acid, base, osmotically extreme (for example very sugary) or other microbially-challenging environments.

Other than sterilization, no method is perfectly dependable as a preservative. That said, really, only foods with a low acidity (most veggies, meat, seafood, poultry and dairy products) need sterilization under high temperatures.  This is achieved through pressure canning.  Foods that can be safely canned in ordinary boiling bath water are highly acidic such as most fruits, pickled vegetables (anything canned in vinegar) or other foods to which acidic additives have been added.

Simply put, if your great aunty (or Teri) gives you jam, jelly or anything pickled in vinegar, it is more than likely okay and most assuredly NOT going to kill you.  The worst thing that would happen is it may not have been sealed properly and it will get moldy.  This is easily seen (or smelled) and should just be thrown out.  If the seal has been compromised at all, again, just throw it out.

Home canning and a bit about botulism

Foodborne botulism (which is what everyone is afraid of getting!) results from contaminated foodstuffs in which C. botulinum spores have been allowed to germinate and produce botulism toxin, and this typically occurs in canned non-acidic food substancesSO, again, simply put, this means that if you get a jar of green beans that are canned in just salt water, not vinegar!,  there is a chance, albeit small, that it has grown botulism.    Botulism is a rare but serious paralytic illness, leading to paralysis that typically starts with the muscles of the face and then spreads towards the limbs. In severe forms, it leads to paralysis of the breathing muscles and causes respiratory failure.  So.  What to do about those green beans.  If Grandma Mary is up to snuff on the latest information on how to pressure can, then I would go ahead and eat them!  The latest recipes have all the benefit of the litigious world we live in and have made it almost impossible (IF ALL STEPS ARE FOLLOWED!) to pressure can improperly. HOWEVER! if she poo poos the latest information and uses old school, or old world methods, I would consider giving it to the mouse outside first and see what happens. (ONLY KIDDING!  I like mice!)

Try the jams, jellies, marmalades, chutneys, relishes, pickled veggies with confidence! And send the thank you note singing their praises. The others may need your brave trust…..or a reserved spot in the pantry to honor the effort. (Really, don’t feed the mice)

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