btw - yes, glass jars have the same considerations as to external
contamination - which is why you are supposed to keep all food in the
refrigerator covered, and use the perishables within a day or two.
(Even if you wipe the jars or cans before putting them in the frig.)

----------

Note that the reason you are supposed to do something is not a guarantee
that something else will happen if you don't. Sometimes it doesn't make a
difference in that time, and sometimes it isn't detectable until much later,
and sometimes you get hit by a truck before your arteries harden.
And sometimes that warning about the truck should have been heeded.


"--" > wrote in message
...
>
> > wrote in message
> oups.com...
> > How safe would it be to leave food in opened cans?
> >
> > I can remember in past days that doing so would cause lead poisoning.
> > I am not sure what they line the cans with now, but I am sure it does
> > not contain lead.
> >
> > How safe would it be to open a can of beans and eat half and put the
> > other half covered in the fridge? Leave it for a day? Leave it for a
> > week?
> >
> > I don't like to wash dishes.
> >
>
> Like most things, it depends primarily on the food and the can.
> Pork-and-beans, the staple of God's food group of fried eggs, fried
> potatoes, and cold canned pork and beans, doesn't seem to have any side
> effects sitting in a can - more likely the users are dying of the grease
> from the eggs and potatoes than from bean cans.
>
> However, like many of these things, in question, the main reason is
missed
> by jumping immediately to the can.
> The can exterior was in the warehouse, on the shelves, and in your
> pantry -
> In that journey from the packager to the refrigerator, the can may have
> been used as a footstool by rats, mice, cockroaches, and other insects
along
> the way (in or out of the box) , and your can almost certainly was handled
> by someone who may wipe their nose on their hand or some like habit, and
> then that hand stocked the can on the grocer's shelves.
> And you want to put that oft-touched can in the refrigerator next to
the
> other food, where the self-defrosting air fan can swirl whatever was on
the
> can into and onto the other food and containers.
> May not be the best of ideas.
>
> background -
>
> 1) Food in a sealed can is kept from changing by storing it in an
> oxygen-free once-heated-to-killing pest-resistant environment. The food
does
> interact with the container, but it's how much and how fast that counts in
> preservation.
>
> 2) Acidity inhibits the growth of many non-aerobic bacteria (basically,
> those that don't need oxygen to grow)
> in that particular environment ( e.g., the botulism-toxin-producing
> bacteria not producing the deadly byproduct in acid foods).
>
> 3) Acid attacks most materials, leeching out the metal and adding it to
the
> food. Again, its the rate and the byproduct created that counts.
>
> 4) The cans themselves are usually made of A TYPE OF steel, and recently
> some are made of aluminum. (It gets a little esoteric, but aluminum cans
> can be thinner than steel, but aluminum cans also are less resistant to
> acids, so for some foods they have to be heavier, defeating their use. And
> rodents can go thru aluminum fairly easily. )
>
> 5) To make a can, the metal has to have certain characteristics to make
> the metal roll without cracks or creases and "weld" properly. (Its often
a
> friction/bending type heating) The steel is alloyed (alloy means small
> amounts of elements like silicon, lead, molybdenum, etc are added to the
> steel allow sliding at metal pressures, malleability, etc)
> In not-so-olden days, the ends were soldered on, using lead-tin. Most
> cans use better methods today.
> Acid apparently leaches lead better in the presence of oxygen. Acid
will
> leech out the alloying elements in steel and aluminum.
> It is doubtful that storing it open once in your adult life is going to
> leech enough metals to hurt you. Throughout your life may. Children
process
> metals more slowly, I understand.
>
> 6) The insides of some canned food types are coated with zinc over the
> "welded" seals and the inside surface (see the insides of a pineapple can
> with that "patterned" look - that's zinc), and some are coated with
plastics
> (the clear yellow-brown tinted stuff aka "lacquer") - to minimize metal
> transfer to the food. Scratches from utensils break that seal. Removing
the
> food to another container removes the contact potential.
> The type of zinc and the process used in food contact were regulated in
> the US, last time I looked. Can't say as to plastic/lacquer either way.
>
> 7) Most plastic (saran being the noted exception) allows moisture to
> migrate - both ways - so keeping a vacuum in most single-layer plastics is
> much more difficult. And smell passes with that moisture to the ten
thousand
> times more sensitive vermin nose, so plastic containers are more
susceptible
> to vermin contact and vermin attack. Mice can chew plastic a lot easier
than
> they can steel.
>
> I personally think that, with a few exceptions, storing food in cans after
> opening is a bad practice, unless you had cooked it over an open fire in
the
> woods.
> And besides, the cans don't microwave at all well. You have to put it in
a
> microwave dish later anyway, so put it in the paper bowl or whatever now
and
> remove all doubt.
>
> fwiw.....
>
>
>
>