Monday, June 9, 2014

Using Vintage and Collectible Ceramics and Glass in the Kitchen and Around the House

Vintage Fiesta Red Platter Showing HLC Fiesta Mark on Back
Vintage Fiesta Red Contains Elements Not in Other Colors

A benefit of collecting pottery and glass is that you never have a shortage of useful bowls, vases or pans, but some vintage and collectible ceramics and glass are not safe for food use. Recent imports are often marked on the back as “Not safe for food” but older and handmade pieces are not often marked. Hazards exist beyond breakage and getting cut, as lead and cadmium poisoning are insidious dangers lurking in these wares. Lead is common in our everyday lives, but chronic exposure to lead or constant consumption of lead causes long-term effects, particularly in fetuses, infants and children.

Ceramics are made of a clay layer and maybe a glaze layer, and either layer can contain unsafe metals and elements, including lead and cadmium. The clay may also be fired only once, creating a bisque without glaze, and elements in the clay depend on where the clay comes from. Some pottery has lead glaze or metal fragments in the glaze, and crystal has a higher lead content than ordinary glass. Any of these may be unsafe in the kitchen.

You’ve probably seen crystal marked 24 percent lead content, and it’s shiny and beautiful, but it’s not good for long-term storage of acids. Liquor stored in crystal decanters can acquire lead from leaching. You can use a crystal decanter, but it’s important to return the liquor to the original bottle after each use. The same is true for acids such as lemonade, vinegar or orange juice. If you serve in crystal, return to another container after the meal.
Block decanter and stopper in clear crystal
Block Brand Crystal Decanter Has Lead Content

Pottery and ceramics are more variable. Contemporary ceramics may be marked as safe for food use or safe for microwave, but the FDA warned several years ago of items from Mexico marked as safe were not.  Sometimes it depends on the glaze color. You may recall that Fiesta red dinnerware had a higher radiation level than other colors, causing concern, and discussed in Smithsonian Magazine. Also, pieces with significant wear to the glaze may leach elements more easily than ceramics with no damage. Microwave use or heating may cause more leaching than serving. It can also depend on age, condition and use. Prior to about 40 years ago, the Food and Drug Administration didn’t test or regulate elements in dinnerware or kitchenware.

Cadmium is present in fertilizers, batteries, plastics and often occurs in association with zinc, as reflected in this CDC report.  Cadmium is naturally occurring in the water and soil, and may be present in the air near iron and steel production facilities. Dyes, paints and glazes can also contain cadmium. Cadmium studies are ongoing, but cadmium consumption may cause kidney stones, kidney diseases and maybe high blood pressure, peripheral artery disease and COPD, according to the Centers for Disease Control.  You can read more about cadmium content in everyday products here on the National Institutes of Health website

Test kits are available for checking lead or cadmium content, but home test kits for cadmium have not been reliable, often rendering false positives, according to the National Institutes of Health. The safest method is to use vintage dishes and accessories for decoration, and use only dinnerware approved for food at the table.   

Use your knowledge to be safe in the kitchen. See you next time!