Peanut butter...

[Externet]

Greetings.

Please move to the appropriate section, as chemistry, biology, nutrition... as deserved.  I do not know where.

What is in the peanut butter product that survives very long time -perhaps years- with no refrigeration, and does not degrade, gets moldy or rots ?  The label of the product does not reveal any preservatives, and I believe it is true.   Is there other legume/nuts/something paste/product that also exhibits such longevity ?

[Genady]

Isn't most of canned food like this?

[John Cuthber]

Heinz used to advertise that "The only preservative we use is the one you open".

[Mordred]

As I understand it, it's due tonhigh fat and low moisture content. 

[TheVat]

"Natural" pb will get rancid after a year or two.  You'll notice it right away - oxidized fatty acids will give it an unpleasant somewhat bitter taste, like old cooking oil.  We found this out when we moved here from another state where we still owned a house.  That house wasn't sold until a few years later and there were a few canned goods and an unopened jar of pb that the relative staying in the house hadn't opened.  It had gone off.  If you want the natural pb to endure, it should be refrigerated.

As for mold, conventional pb has additives that inhibit mold.  Natural doesn't, so once it's opened it's capable of going moldy.  But it won't be aflatoxin, unless you're in some country with lower regulatory standards for peanut processing.  IOW aflatoxin won't get in there from spores in your house.

[John Cuthber]

4 hours ago, TheVat said:

IOW aflatoxin won't get in there from spores in your house.

It will if you are unlucky.

[TheVat]

 

3 hours ago, John Cuthber said:

It will if you are unlucky.

I should clarify:

7 hours ago, TheVat said:

aflatoxin won't get in there from spores in your house.

if you live in a developed country.  Very low probability.

In third world countries, especially in the hot and humid conditions of those in the tropics, aflatoxin is a serious public health problem, both in agricultural storage of nuts and grains, and in its infiltration of residences.

I was addressing the OP, who IIRC resides in the UK.  Where aflatoxin in peanut butter (above permissible levels) would be extremely rare.  Imported nuts and maize are inspected carefully, especially if they are from the Global South.

(one reason I'm familiar with this topic is that a family member got pretty ill eating peanut butter some years ago, and we did some research)

[StringJunky]

If it's heat-treated prior to filling whilst hot, the partial vacuum in the residual space after cooling will arrest the spoiling process for some time. This is lost once it is open ed. This is how the general canning process works as well. I'm guessing that peanut butter in plastic jars are chemically preserved, since the container would deform with heat.

Edited June 2 by StringJunky

[Externet]

12 hours ago, Genady said:

Isn't most of canned food like this?

The longevity shows a loooong time after first opening the jar, slowly consumed along many months, perhaps to a year with no signs of degradation 

[StringJunky]

30 minutes ago, Externet said:

The longevity shows a loooong time after first opening the jar, slowly consumed along many months, perhaps to a year with no signs of degradation 

Probably synthetic preservatives.

[Genady]

38 minutes ago, Externet said:

The longevity shows a loooong time after first opening the jar, slowly consumed along many months, perhaps to a year with no signs of degradation 

My peanut butter does not do this. The answer is elsewhere.

[sethoflagos]

2 hours ago, TheVat said:

In third world countries, especially in the hot and humid conditions of those in the tropics, aflatoxin is a serious public health problem, both in agricultural storage of nuts and grains, and in its infiltration of residences.

I'm sure some supermarkets must stock it, but I don't recall seeing peanut butter in Nigeria. It's very much a US product.

Here, processed peanuts yield peanut oil and the dry product kuli-kuli which is mixed with various peppers to yield our signature barbeque spice mix suya.

Peanut oil and suya pepper have a pretty well indefinite unrefrigerated shelf life even in our climate.  

[Externet]

27 minutes ago, sethoflagos said:

Peanut oil and suya pepper have a pretty well indefinite unrefrigerated shelf life...

That is what I noticed...

[John Cuthber]

On 6/2/2024 at 11:50 PM, TheVat said:

 

I should clarify:

if you live in a developed country.  Very low probability.

In third world countries, especially in the hot and humid conditions of those in the tropics, aflatoxin is a serious public health problem, both in agricultural storage of nuts and grains, and in its infiltration of residences.

I was addressing the OP, who IIRC resides in the UK.  Where aflatoxin in peanut butter (above permissible levels) would be extremely rare.  Imported nuts and maize are inspected carefully, especially if they are from the Global South.

(one reason I'm familiar with this topic is that a family member got pretty ill eating peanut butter some years ago, and we did some research)

We need to clarify something. Wiki tells us that:
Aspergillus flavus is a saprotrophic and pathogenic^[1] fungus with a cosmopolitan distribution.

So, its spores can get into a jar no matter where you open it.
The rich countries have resources to test peanuts for aflatoxins before they get into the human food chain.

But, once the jar is open, the only thing preventing this "aflatoxin won't get in there from spores in your house.", is luck.

I am pretty sure that the manufacturing process (and certainly the canning process) will kill the fungi that produce mycotoxins (thought they may not destroy toxins which are already present).
The lack of water (because it was lost during roasting) makes it unlikely that microorganisms will thrive in peanut butter. (Salt and sugar may also act as antimicrobials.)

That will not prevent spoilage completely. Oxidation will happen once the product is exposed to air.
There may well be antioxidants in commercial peanut butter. Those are not typically thought of as "preservatives".



 

[TheVat]

2 hours ago, John Cuthber said:

But, once the jar is open, the only thing preventing this "aflatoxin won't get in there from spores in your house.", is luck.

Hence my posting that the probability is low, not zero.  I seem to keep referring back to points I thought I already made, and dealing with partial quotes that have been misunderstood.

For the last effing time:  aflatoxin, though widely distributed, is not sufficiently concentrated in northern European houses (the OP context to which I was replying) that it would likely get into peanut butter.  Hence my comment:

On 6/2/2024 at 4:50 PM, TheVat said:

Very low probability.

Ciao.

[CharonY]

I think prevalence of the fungus in Europe, incl. UK. However, all things considered, it is more likely found in a damp and forgotten corner in your home than in you peanut butter jar.

If we talk specifically about aspergillosis rather than general fungal infections, the highest in Europe are in Greece and Ireland, UK is a bit lower. Mexico is a bit lower than UK, and the lowest surveyed are Canada, Russia, Sri Lanka and Portugal. It is likely not only weather but also how homes are built.

[TheVat]

Just to be clear, re PB.  Aspergillosis is a pulmonary infection or allergic response to the airborne fungal spores.   Aflatoxins are secondary carcinogenic fungal metabolites from various Aspergillus species.  It is the latter that is the concern with peanuts, maize, etc from certain agricultural regions where there are issues with storage and inspection, e.g. Zimbabwe.  Because PB is a poor growth medium (as others have mentioned here) for Aspergillus, the production of significant amounts of its aflatoxin metabolites is very unlikely.  

It's a bit like radioactive isotopes.  They exist in small amounts in almost everything, but usually producing levels of ionizing radiation that are harmless.  Aflatoxin is similar.  

Edited June 4 by TheVat
add

[CharonY]

Food in Europe is tested which provides safety (and luckily EU levels are on the stricter side) , but there is increasing concern that also in Europe grain and maize can be increasingly contaminated ( beyond what is already the case). Does not affect PB as long as food testing is done. But in recent years recalls due to exceeding mycotoxins limits have increased. But you are right if it wasn't there already due to contamination, you probably will notice mold before dealing with the toxins (there is arguably a transition period where some mold may be invisible to the naked eye while toxins might be able to do low level harm). 

I think my overall off topic (and preachy) point is that dangers to the food chain are often way closer than we intuitively think.

[John Cuthber]

13 hours ago, TheVat said:

Hence my posting that the probability is low, not zero.  I seem to keep referring back to points I thought I already made, and dealing with partial quotes that have been misunderstood.

For the last effing time:  aflatoxin, though widely distributed, is not sufficiently concentrated in northern European houses (the OP context to which I was replying) that it would likely get into peanut butter.  Hence my comment:

Ciao.

https://mft.nhs.uk/wythenshawe/services/respiratory-and-allergy/national-aspergillosis-centre/
The fungus  really isn't that rare in the UK.
And you really did say, absolutely, that it wouldn't happen.

 

On 6/2/2024 at 3:55 PM, TheVat said:

aflatoxin won't get in there from spores in your house.

It could, and there's nothing the food standards authorities can do about that. On the other hand they can test for aflatoxin in peanut butter (and insist on good storage etc.)

There are two factors.
The toxin already being present in food and the mould infecting food later.

Your post muddled them.

 

On 6/2/2024 at 3:55 PM, TheVat said:

  Natural doesn't, so once it's opened it's capable of going moldy.  But it won't be aflatoxin, unless you're in some country with lower regulatory standards for peanut processing.  

I was trying to sort them out.
 

Edited June 5 by John Cuthber