I am not aware that "tin" cans for foods include zinc in the tin plate.  Though the term galvanized is applied to such materials as hardware cloth and steel pipe for plumbing, the coatings are mostly zinc, not tin.  Not the case with food cans.  BTW, some of those are tin coated.  Others are called tin cans for historical reasons, but are steel only.  Here is what Wickipedia says on the subject:

http://en.wikipedia.org/wiki/Tin_can

mcneely

---- Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM> wrote:
> all right..
> I'll check it out.
> I always heard they were pretty poisonous. .zinc fumes.
>
> Scott
> ----- Original Message -----
> From: "David Beierl" <dbeierl@ATTGLOBAL.NET>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Saturday, January 07, 2012 6:19 PM
> Subject: Re: Tin-can westy toaster
>
>
> > At 09:04 PM 1/7/2012, Scott Daniel  - Turbovans wrote:
> >>in case anyone doesn't know..
> >>galvanized metal..
> >>when heated enough emits a deadly poison.
> >
> > Zinc fumes aren't good for you, but they're hardly deadly.  Here's a
> > good writeup on "brass-founder's ague."
> > http://phr.emrystick.com/patient-education.aspx?medical-term=metal-fume-fever
> >
> > Yours,
> > David

--
David McNeely