Food cans

Gretchen Voeks <Gretchen_Voeks<-a t->nps< . >gov> writes

>Does anyone have experience, information, opinions, etc. on the
>conservation of tin cans of foodstuffs? I am particularly interested
>in the issues surrounding the potential for these cans to present
>biological hazards. Presently I have a few fruit and soup cans which
>were placed in a freezer three years ago, which caused them to
>expand and bulge and I expect them to corrode along stressed areas
>if they are removed and thawed. If the foodstuffs will present a
>potential hazard, what are the risks to staff and how do we dispose
>of the contents? Are the hazards associated with all canned foods or
>are only meats a problem? These cans were produced c1915.

First, a few thoughts on your query: The expansion and bulging of
the cans in the freezer is possibly due to the expansion of frozen
water in the can. My understanding is that most food stuffs will
present a hazard after a time, not just meat.

A number of years ago at the Museum of Modern Art, we treated two
Campbell Soup cans--Tomato Beef--signed by Andy Warhol, dated 1964.
The cans were not bulged out with gasses generated by botulism
bacteria because the soup was acidic and had eaten tiny holes
through the metal.  The cans were, of course, leaking. The cans were
rusted overall.

I called the Campbell Soup Company who informed me that the cans
were reeking with toxic botulism and I should discard them in the
trash. They guarantee their cans for three years only and they were
very, very upset that we had cans that were 20+ years old.  The more
I tried to explain about works of art, the less they understood.

I won't go into the complete treatment which involved preserving the
labels.  The paper labels were protected with a paper wrap in situ.
We tested 5 or 6 can openers to get one that gave a clean cut.  We
opened the bottom lids of the cans in a fume hood.  We protected
ourselves by wearing rubber gloves and protective clothing.  Once
the cans were opened we dumped the contents in the toilet and
flushed.  We rinsed the cans with alcohol and acetone, being careful
not to get solvents anywhere near the labels, which are usually
quite solvent sensitive.

The lids were readhered with an epoxy loaded with aluminum powder,
and inpainted to look as rusty as before.  We also filled the cans
with wax to the correct weight, to give them heft.

In another treatment (not at MOMA) of similar Warhol soup cans,
there was a price label on the top of the can, which the owner
wished to preserve in situ.  Fortunately, that label was easily
removable and two small holes punched in the can lid allowed the
contents to drip out.  The same rinsing procedure was followed by
filling and regluing the label in place.  In that case, I filled the
can with glass abrasive beads which sloshed as the can was turned.

Lynda Zycherman
Associate Conservator of Sculpture
Museum of Modern Art
New York
212-708-9571

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                 Conservation DistList Instance 10:103
                  Distributed: Wednesday, May 21, 1997
                       Message Id: cdl-10-103-001
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