> 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.....