North American Fruit Explorers mailing list at ibiblio

[Douglas Woodard <dwoodard@becon.org>]

Regarding "canned goods are safe to eat as long as the lid hasn't popped 
up":

There is an assumption here that if yeast etc. which produces gas is not 
growing, the Clostridium botulinum isn't growing. I wouldn't want to bet 
my life on this. I don't know how much gas C. botulinum may produce. I 
recall that C. botulinum survives temperatures which kill other organisms.


Regarding whether citric acid will intensify flavour: All other things 
being equal I would expect so. I suggest that you experiment with a 
small batch to find out whether all other things are indeed equal.

I recall reading that in old times the juice of sour crabapples 
(verjuice) was used as we now use lemon juice. I think that we may have 
to return to this in an energy-frugal future with less industry and 
transport. Possibly "sharp" cider apples would have application here. 
One would want initially to measure the pH of the particular juice (or 
the final mixture), remembering that growing conditions and ripeness may 
affect the pH to a degree. The flavour of the juice would be important.

Doug Woodard
St. Catharines, Ontario, Canada



Mark Angermayer wrote:
> Doug wrote:
>
> " Around 1980 I read up on botulism and pH. It seemed that there was a
> > little uncertainty about pH levels between 4.0 and 4.4, especially with
> > high-protein materials like meat and beans. pH levels not over 4.0
> > seemed to be regarded as safe. If you are canning anything but fruit
> > puree or small chunks I would recommend that you read up on the latest
> > scientific opinion, and think about pressure canning. I wouldn't take
> > chances with botulism."
>
>
> Good information Doug.  Thanks.
>
> I did have one question.  I'd always heard canned goods are safe to eat as
> long as the lid hasn't popped up.  Is this true, or a myth?
>
> Also I looked on line and found this website of pH values for various foods:
>
> http://www.cfsan.fda.gov/~comm/lacf-phs.html
>
> Here's what they have about peaches:
> Peaches 3.30 - 4.05
> Peaches, canned 3.70 - 4.20
> Peaches, cooked with sugar 3.55 - 3.72
> Peaches, frozen 3.28-3.35
>
> I'm sure these values aren't absolute, so I think next time I make jam, I'll
> go ahead and add a little citric acid.  We add it to our salsa when we can,
> to increase acidity for safety reasons.  Based upon what you said about
> lemon juice intensifying flavor, I wonder if citric acid would do the same
> thing?
>
> Mark
> KS
>
>
>
>
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