Full disclosure time, folks. I’ve been poisoning you.
But just a little bit.
Thanks to Mark, i’ve discovered that the underside of most canning jar lids sold in this country, including the ones i’ve been using, is now coated with a plastic that contains BPA, which is much in the news since California is on the brink of banning it in baby bottles, a ban which had previously failed owing to heavy lobbying from folks that sell products containing it. Ah yes, good old American free enterprise, the right to bribe congressmen to vote against regulation of stuff that scaredy cats like the FDA and AMA say is poisonous.
So yes, if you store a jar of my jam upside down so that the underside of the lid is in contact with the contents, some tiny amount of BPA will leach into the food. And if the jar gets shaken in transit to your cupboard, a more miniscule amount gets into your food.
In other words, Be Afraid. Be Slightly Afraid.
On the other hand, if you ever eat or drink anything that’s been in a can, you’ll be exposed to vastly more BPA since the entire inside of the can is lined with the same BPA-containing plastic. And too, many of our plastic food storage containers are rich sources of BPA (and other horrible stuff like phthalates. My preliminary research suggests that plastic containers with the resin identification codes 3, 6, and 7 are the ones to watch out for and that BPA is found only in code 7 plastics).
Actually, BPA has been leaching into our foods since the sixties, so us old farts might as well not worry about it. On the other hand, if you have kids you might be thinking about how you can limit their exposure. Like by reducing the amount of canned foods you serve ’em and by doing your own homework on which plastic food storage containers are safer.
And by storing Matte’s jams and jellies in the upright and locked position.