Dried fruit question: to eat or not to eat?

This past summer we had a bumper crop of peaches. After eating the juicy fruits fresh, sharing with the neighbors, freezing peach halves, and canning preserves, we still had more peaches. So I dried peaches, stuffed them into airtight quart jars and hid them in the back of the fridge for holiday baking. The peaches were not sterile, just clean, pitted, and dried to a moist flex stage.

Yesterday, 3 months later, I opened a jar. Upon exposure to air, the peaches started to expand and over flow the jar! The color is bright, no fermentation smells, no liquid pooled at the bottom of the jar. Yet serving them fresh worries me. Had something grown inside the jar: could it have been the dreaded botulism toxin??? If these were canned peaches, I would have followed the rule, “When in doubt, throw it out.” But these are dried peaches, not canned. Is the expansion of dried fruit normal?

The beautiful bounty was to be the basis for holiday delights and is now on hold pending Permies discussion. I’m not eating or baking with them raw until I learn how to discern whether or not the expanding peaches are safe.

In the mean time, I am eating the peaches after rehydrating in water for 2 hours, bringing to a hard boil, then simmering for 15 minutes.  

Please weigh in here: you will not be held responsible for the outcome!

I have dried a LOT of fruit, stored some of it for over 10 years before eating. I have NEVER seen that. I'd guess they were not thoroughly dry.
I'd be very disinclined to eat them, personally.

Thanks for your opinion on this question Pearl!
How does one measure or discern "thoroughly dry?"

That's so... bizarre! I wonder if there's a local college or extension office that might be able to test them, and at least tell you why they did that, to help you prevent it from happening, again? But, I'm with Pearl, and your 'when in doubt...' instinct.

"Thoroughly dry" in most cases, means brittle, or at the very least, stiff leather. The way to know if something is sufficiently dry is by conditioning. You put the dried food into an airtight jar and leave it for a week, at room temperature, checking daily, for moisture in the jar. It would normally appear as condensation on the inside of the jar. If there is ANY sign of moisture, you'd return it to the dehydrator, and start the process again.

Thank you Carla for your insights!
The texture of these peaches was like store-bought packaged raisins, prunes or apricots: soft and somewhat moist. Like raisins, prunes and dried apricots, the peaches were not brittle or leathery.

Amy Gardener wrote:Thank you Carla for your insights!
The texture of these peaches was like store-bought packaged raisins, prunes or apricots: soft and somewhat moist. Like raisins, prunes and dried apricots, the peaches were not brittle or leathery.

They get that effect by dusting the fruit with sulfides as a preservative before drying them. Un-dusted fruit I agree with Carla's definition of "dry" to snap, or bending if it's thin leather.

My mom added "There are other things than botulism that aren't good to get in you." She has dried fruit for 40 years, and was horrified when I read her your post. She's never seen anything like that.

Well I learned something new about how dry is dry! Thank you Carla, Pearl and Pearl's Mom.
I'll cook these peaches thoroughly before topping my oats and won't serve them to guests. I really appreciate the expertise and caution here.

Amy Gardener wrote:Well I learned something new about how dry is dry! Thank you Carla, Pearl and Pearl's Mom.
I'll cook these peaches thoroughly before topping my oats and won't serve them to guests. I really appreciate the expertise and caution here.

You're braver than I! And yes, as Pearl said, the reason store bought dried fruits are so soft is because of the sulfur and... other stuffs. But, honestly, I wouldn't even put them to my lips, much less actually ingest them.

How fast di they expand? Is it possible they were just rehydrating in the warm kitchen?

Echo what MK just said...we dry lots of fruit and put lots of the apple slices away in jars with locking lids. If the dehydrator runs a bit longer than planned, they get so  dessicated that they're crispy. The first time the jar is opened they're still super dry and you can just tip out the dry pieces like massive cornflakes, but in humid weather they swell up in a day or so and you need to dig to get them out...and they're no longer crispy, just more like "normal" dried apples.

Not much can go wrong with fruit as long as it's got decent sugar levels and the moisture content is low enough.

Thank you MK & Phil for the reassurances based on your experiences! Your observations are consistent with those of a few neighbors who also preserve fruit by drying. To answer your question MK, the peaches expanded immediately upon opening and continued for about 5 seconds.
When stuffing the peaches in quart jars tightly, I probably closed the air spaces within the peaches before closing the lids. I agree that putting the room temperature jars in the coolest part of the fridge probably influenced the expansion when the contents hit the warm and humid kitchen. The peaches expanded and ballooned out of the narrow necked jar by about 2". There was zero liquid pooling in the jar so the peaches were probably dry enough.
Just in case, I played it safe by rehydrating for 2 hours then cooking the peaches for 15 minutes. The flavor was sweet and delicious.
But I would have loved to use those peaches dry. Next time I will let the fruit containers warm to room temperature before opening. And I won't over stuff the jars!

Carla Burke wrote:

Amy Gardener wrote:Well I learned something new about how dry is dry! Thank you Carla, Pearl and Pearl's Mom.
I'll cook these peaches thoroughly before topping my oats and won't serve them to guests. I really appreciate the expertise and caution here.

You're braver than I! And yes, as Pearl said, the reason store bought dried fruits are so soft is because of the sulfur and... other stuffs. But, honestly, I wouldn't even put them to my lips, much less actually ingest them.

I'm with Carla on this one.  With a lot of biological food contaminants it isn't the bacteria or fungus that makes you sick.  It's the metabolic by-products that make you sick.  I'd be really hesitant to eat these until an expert weighs in.  The suggestion of asking an extension office sounds like a good idea.

If they do not smell bad or look bad, then eat them.  Use them in a stewed fruit dish if you are worried.  They are natural and wholesome.  Humans have been cooking and preserving for millenia without refrigeration and we have survived as a species.  Don't worry, eat them.

Amy, thank you for the explanation that the peaches have been cooked and tasted sweet and delicious.

I was sad thinking the peaches were going to be trashed.

I can't think that you would have got that much expansion just by thermal effects that quickly. Were they taken straight from the fridge and opened, or brought up to room temperature first and then opened? If the latter I suppose it is a possibility. However my suspicion is that there may have been a very slow fermentation going on. I don't think botulism is likely in a dried fruit product - I think that is more likely in preserved vegetables. Acid and sugar make it less likely I believe. However if there was some live yeast that might have been, if not happy (due to the cold) at least respiring and creating a bit of pressure in the fruit jars.
I thought it was odd that you stored your dried fruit in the fridge, but perhaps it is just as well, since they may well have exploded in a warmer environment. Probably as well to use the rest up sooner rather than later, just in case.

I just found a tub of dried plums from 2018's harvest. 6 years ago.  Opened them up and they are still brittle.   Going to pour some hot water on a handfull, and when they are cool enough, they make like a stewed plum.  Very tasty.

Soft drie seem to taste bad after about a month.