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Blue/green fungus on beans


By balcony


Last month, September, I harvested a bed of Pinto beans from my allotment, Plot 12A, & after a few days dying in the greenhouse my wife removed all the beans from the pods. We took them home & spent the best part of a day “drying” them in the oven. Or at least that what we thought! I set the oven on the lowest setting & left the door closed but not shut completely as I thought they would need the air circulation to dry properly. I put them in, in batches, on an open mesh tray for pizzas on a sheet of kitchen paper. After 15 mins I went & moved the beans around a bit to make sure of even drying. After a further 15 mins I took them out & put in another batch & repeated the process. I probably did about 6 batches in all. After taking them out of the oven I spread them out on a couple of sheets of kitchen paper to cool down. After an hour or so I put each batch in a plastic bag & put them in the cupboard.

After about a week we noticed a bad smell in the kitchen, we thought it was from the rubbish/trash bin so I emptied it out & put a fresh bag in it. The next day the smell seemed stronger & then it suddenly occurred to my wife that it might be from the beans as the smell seemed strongest near the cupboard. I got the bags of beans out & effectively, it was the beans! Some of the bags had clumps of beans all stuck together & when we emptied one of the bags the smell was overpowering! As it seemed to be starting off in the lower part of each bag I took the bags out onto our balcony & emptied them all on a big table we have out there to dry for a day or two. They have been out there a week now but they haven’t dried off very much. I’ve moved them around a bit each day to try to get them to dry.

We had one bag that was filled with beans brought home at least a week after the first. Obviously these were the last to dry & we cooked some last week. They were very tender.

After all that l-o-n-g-w-i-n-d-e-d explanation what I would like to know is would they be safe to eat? We have removed all the beans we could find that showed the slightest sign of this blue/green fungus on them & you can see them in the photo. Those that were left have gone back into the oven set on a higher temp & with the door shut this time. They have also been in for 3/4 of an hour instead of 30 mins as the first time.

Does anybody know if this fungus produces anything toxic for humans? It would be a crying shame to have to throw away 3 or 4 kg of beans as they would last us all winter! On the other hand we don’t want to become ill!

Can anybody point me to site where they explain exactly how to dry & store home harvested beans? I have more plants on the allotment that will have to be harvested in a couple of weeks time.

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Hi Balcony ...
I hope you get the information you need...

3 Oct, 2012


I hope so, too! You're really "on the ball" again! I only published the blog about 10 minutes ago!

Oh, oh, got to run & take the latest batch out of the oven!

3 Oct, 2012


Lol. :o)))

3 Oct, 2012


I dont know anything about Pinto Beans, but nature means Runner Beans to dry off in their shells.
I have some lying on a window sill without any heat, which will dry too much and be useless, and some still hanging on the vine which are fine.
These will be removed and saved in a dry place for next season.
I wouldnt eat those mouldy beans.

4 Oct, 2012


Thanks, Diane, we've got rid of the mouldy beans. There are far too many plants of Pinto beans to leave to dry naturally. They stayed in the ground till they had begun to turn yellow. Some of the plants had dried up before I harvested them. When I do my next blog on the allotments, probably next week, I will include a few pictures of Pinto beans, at different phases.

The Pinto beans are a fairly short climber - not at all like Runner beans & the beans are dried off to be eaten at a later date. You can find them in the supermarkets, in the section dedicated to Pulses. That's where we buy them. We also buy Lentils (not split) & Garbanzo beans, (aka Chic peas).

4 Oct, 2012


I'm sorry to hear about your beans but I'm afraid I can't help. I hope you get an answer from somewhere as to whether you can eat them or not. As you say, it would be a shame to waste them ...

4 Oct, 2012


Thanks, Hywel. We put a lot in the oven again at a higher temp & for longer. They6 are now mixed with dry rice so I hope this time we have done the right thing!

6 Oct, 2012


Hi Balcony.
I suggest that you give the beans a short boiling water dip right after harvesting. Then let them dry.

This blue/green fungus also appears on some bean seeds that germinate on moist kithenpaper. I added photo "Blue green fungus on bean seeds" at "Garden Pictures".
I use this germination method to grow small bean plants indoors and to plant them in the garden soil. Bean seeds with blue fungus do not germinate well and give a bad smell.
When dry bean seeds get a short immersion (10 - 20 seconds) in boiling tap water, there is (almost) no fungus on the beans during germination. So boiling water "deletes" the fungus traces on dry beans.

Greets, Sjef.

13 Dec, 2012


Hi Sjef, welcome to GoY!

Thanks for that information. They weren't dried enough in the oven & when put in plastic bags they obviously sweated & then the fungus grew. I threw the majority away but those that didn't show signs of this fungus I put back in the oven for a longer period of time & at a higher temp. When they had cooled I put them in plastic bags again but mixed in with some dry rice. They were OK & we have since eaten them with no ill effects. :-))

As I have brought some more home from the allotment I will heed your advice & put them in boiling water for a few seconds. Thank you for your advice! :-))

I hope we will see more of you on GoY! :-))

14 Dec, 2012


Hello Balcony,

Thanks, I'm glad that my tip can help you. And that you did not get ill.
The GoY site is new to me. I found it when I googled "blue fungus on beans".

I have some questions/remarks.
- I added a photo about the fungus at "Garden Pictures", as extra information. How can this photo be put in my former comment? Or can someone make a link to this photo in that comment?
- About your harvested beans: I think that the beans have been dryed for a too short time. And when packed in plastic bags, they could not dry anymore.
When I harvest dry beans, I pick "almost dry" pods with seeds from the plant. I put the pods in a plastic net (as used for packaging oranges or mandarines). I hang the net under a roof in the open air and let the pods dry for 2 to 4 weeks. Then I take the beans out and let them dry on kitchen paper indoors for some days.
The dried beans are stored in a box made of paper (thin cardboard). I use empty rice or macaroni boxes of 400 to 500 grams. These boxes are not airtight.
I never saw fungus on these beans.
- On my weblog you can find many useful tips for a vegetable garden.

Greetings, Sjef.

14 Dec, 2012


You can't add photos to comments I'm afraid. I wish it were possible but it isn't - not on GoY at least. You can do it on other gardening sites like MyFolia.

I've had a quick look at your site & find it quite impressive! Your tips are very well explained, it must take you a long time to go through every little step & add photos to the steps as well!

I just looked up "blue fungus on beans" & found my post on here was the 2nd that came up! Not much help though!

I also realized that the beans hadn't been dried for long enough! I'm still experimenting though! I didn't want to "cook" them, only dry them. That's why I used a low temp & left the oven door open a little.

Since I did the surviving beans a 2nd time they have been alright. We still have some that haven't been cooked yet. We will probably eat them in a week or so.

16 Dec, 2012


Thanks for the quick look at my weblog. Gardening is a big hobby of mine. I'm retired since January 2011, so I've time to think, do, make photos and fill my weblog.

One more thing about dried beans:
When you store them for a long time (several months), maggots or "maggot babies" can appear between the beans.
To overcome this problem put the dried beans in a plastic bag and put the bag with beans for 24 hours in a freezer at - 18 C (0 F). Then take the beans out of the plastic bag and store them in a paper bag or paper or cardboard box or so. I've tried it and it works well, no maggots or any other little animals to be seen.
This method is well known at the internet.

17 Dec, 2012


That's another great tip! Thanks very much! :-))

18 Dec, 2012

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