How do folks make sun dried tomatoes without bacteria or bugs ruining the tomatoes?

Question

That’s pretty much the post, I have always eaten them without knowing how they are safe to eat.

In: 869

Answer 1

The truth is they are very rarely sun dried. I make ‘sun dried tomatoes’ all the time. In my dehydrator.

But like anything preserved, the ‘old’ time honored way is salting it and/or smoking it. Jerky, fish, preserved meats, what have you. There are other ways. Cheeses form a rind of mold. Or we protect it with wax. Vinegar pickles things; bacteria don’t like that. We make preserves by adding a ton of sugar, then gelatin to firm it up. Boiling it kills the nasties, sugar makes them stay away.

The real question is ‘how do we make things unpalatable to bacteria/insects’ and the answer is: too salty, too sweet, too acidic or any combination thereof.

Edit 1: Yes, there are also physical methods. I also once made a tray of screen between to pieces of wood; I actually made a stack of five with a little lock on them to also keep raccoons and varmints out, but again, the chemical means are the ones we use most and most effectively. Mostly, salt or sugar.

Edit 2: Actually going beyond eli5 and making it like, eli 15 or so (because I can’t help myself) the reason this all works is basically scale. I’m 6’1, 230 lbs. If a grain of table salt touches me, well, fine. Your standard fruit fly is… much smaller. If it touches a grain of salt, half the liquid leaves its body and it dies. If a single celled organism comes within the range of diffusion of a grain of salt, it’s membrane ruptures and it bleeds out instantly. So we can consume (comparatively) HUGE quantities of salt, sugar, vinegar, etc, with (virtually) no consequences, whereas it is absolutely mortal for tiny bacteria and insects. The chemical process is still the same; eating salty, preserved food will dehydrate a human. Then we just drink a bunch of water, because the process is slower inside of us. Its the same with say, alcohol. Alcohol will instantly rupture the membrane of a bacteria, because the rate of diffusion will cause it to explode. It works the same inside me, but it will take another 10-20 years, because I am so large.

Edit 3: In America they are rarely ‘sun dried.’ Nothing in an American grocery store is ‘natural.’ We mass produce food. If you bought ‘sun dried tomatoes’ in a jar, they were dehydrated in an industrial dehydrator on a conveyor belt, slid into a jar filled 1/4 with oil, topped off and capped by a machine. Same with your mangoes, pineapple, whatever you want. We have a machine for that. Other countries, I can’t comment on.