When it’s time to make sauerkraut and other preserves for winter, you may reach for a stoneware crock. Maybe you found an old one you liked and wondered if it was safe to use for pickling cucumbers.
Older containers come with a few potential dangers: lead in the glaze or paint, and cracks or chips that could harbor bacteria.
When old crocks were made, those dangers weren’t well known. Modern scientific research has pointed out the risks and manufacturing has given us safer options such as crocks with lead-free glaze.
Fermenting in particular gives lead more time to leach out into the food as it sits in the container for a long time.
Maybe your crocks have been passed down for generations. If your family members survived, why should you reconsider using their stoneware?
Laurie Bowen, a food safety educator at the University of Maine Cooperative Extension, hears that question a lot. She answers that the science we understand and the food we eat have changed significantly.
For one thing, she said, we just don’t know how people were affected in the past, especially over lifetimes of exposure. Our food system is much bigger than it used to be, and what you buy at the grocery store could come from all over the world, where food safety regulations may be different.
“There are all kinds of changes to factor in to how we’re eating,” she said.
Today, most lead exposure in the United States comes from house paint, not dishes, and the federal government has regulated lead in new products since 1971. The allowable level has changed over the years, and no amount is considered safe for human health, according to the agency.
In their day, potters had reason to use lead. It helped melt the glaze that forms a water-tight coating over porous clay. It also makes red, orange and yellow colors look brighter and last longer.
If a piece of pottery is fired at the right temperature for the right length of time, lead is bound into the glaze and won’t get into food in harmful amounts, according to the Food and Drug Administration. But if it isn’t, it could contaminate the food.
Lead poisoning is a particular health risk for kids and pregnant women, causing issues such as miscarriage, premature birth, low birth weights, developmental delays or brain damage. At lower levels, adults can suffer higher blood pressure and problems with their brains, kidneys and reproductive health.
There are some differences of opinion about their accuracy for home products, but you can buy a testing kit with a swab that changes color if it comes in contact with lead. Do a few tests to make sure you didn’t get a false negative. The Environmental Protection Agency recognizes one, D-Lead, for use by certified testers. It’s also sold to the public.
To be on the safe side, use your heirloom crocks for decoration rather than fermenting, Bowen said.
If you don’t want to buy new stoneware, you can also use glass containers you already have, such as canning jars.
Food-grade plastic is an option too. The symbol on the bottom of the container tells you what type it is. Numbers 1, 2, 4 and 5 are considered safest for food storage — categories that include juice and milk containers, bread bags and medication bottles — though they may still leach chemicals over time.
No matter the container you’re using for food preservation, make sure you take care of it and watch out for cracks or chips, Bowen said.
