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Path: utzoo!linus!philabs!seismo!harpo!eagle!mhuxl!mhuxh!edelson
From: edelson@mhuxh.UUCP (edelson)
Newsgroups: net.cooks
Subject: Re: Lead poisoning and ancient Rome - (nf)
Message-ID: <1248@mhuxh.UUCP>
Date: Thu, 22-Dec-83 10:29:13 EST
Article-I.D.: mhuxh.1248
Posted: Thu Dec 22 10:29:13 1983
Date-Received: Fri, 23-Dec-83 04:38:41 EST
References: <2074@fortune.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 25

Glazed ceramic articles sold for food use in the US have to pass
tests for lead solubility.  This applies to articles manufactured in 
the US as well as imports, where the testing falls under the aegis of
the US Customs Service.
Certain ceramic artwork (like plates, bowls, etc) which do not pass
this test will bear the mark on the bottom "Not for Food Use."
The things to watch out for are ceramics which are purchased out of
the country by tourists and are brought in beyond the range of normal
imports and escape this inspection.
If in doubt, a simple test can establish whether there is any ground for suspicion:
             
       Place a drop or two of an acidic food (vinegar, lemon juice) on a
glazed area (preferably on the underside of the piece so that any damage
will not be obvious).
           
      Let it sit for several hours and wash it off.
           
      Inspect the piece for any dulling of the glaze.  A sensitive way of
doing this is to try to write on the glaze with a soft lead pencil.  If the
pencil marks the test area, it means the food has dissolved some of the ceramic.               
      This does not mean the piece is unsafe for food use, since the glaze
may not contain any poisonous heavy metals.  To confirm whether lead is
present requires a further chemical analysis which is best left to 
professionals.  However, play it safe and put the piece away in the
breakfront to be looked at only.