BPA, or bisphenol A, is an industrial chemical used in some plastics and epoxy linings of metal food cans. Some studies have linked it to cancer and thyroid dysfunction, causing manufacturers of baby bottles and food storage containers to offer BPA-free products. Canned tomatoes are of particular concern, since their high acidity can cause BPA to leach out over time, particularly if the can is scratched, dented, or otherwise damaged.
We sent cans of diced tomatoes to a lab to test for BPA. The results showed amounts of BPA ranging from 0.33 micrograms to 17.4 micrograms per can. The Food and Drug Administration has never issued official guidelines for safe levels of BPA in food (the agency merely concedes it has “some concerns” over BPA exposure and has promised to study the issue). But in 1995, the Environmental Protection Agency established a daily reference dose that is likely to be without risk: 50 micrograms per kilogram of body weight for adults, or 3,400 micrograms per day for a 150-pound person. If these numbers are correct, our lab test indicates that canned tomatoes contain low levels of BPA.
Even if the government doesn’t prohibit the use of BPA in can linings, consumers are pushing manufacturers to develop BPA-free alternatives. With canned tomatoes, the difficulty is finding a replacement lining that can resist tomatoes’ acidity, which can corrode an unlined can. One solution, though expensive, is to pack tomatoes in aseptic cartons. (Unfortunately, the only brand we know of that currently does this is Pomì, which we don’t recommend.)