Shelf life of MAQs - in the freezer.

[Amari]

I bought a box of 10-treatments MAQs at the BBKA Spring Convention in April this year. It was reduced in price because of the imminent expiry date - July. The vendor told me the expiry date can be lengthened by storing in a freezer where they have been ever since. I used two treatments in August on my two hives on the heather but couldn't test the Varroa drop because of the travelling distance. I used ApilifeVar on my hives in the home apiary.
Does anyone have experience or have knowledge of how long I can store the MAQs before use? The box merely states 'Store in a cool place'.

 

[domino]

http://www.beesource.com/forums/sho...-recieve-Federal-Approval&p=653617#post653617

This chap claims to have emailed the manufacturer who confirmed this.

It's the Internet so I'd take it with a pinch of salt.

 

[user 6228]

there's this:
The Decomposition of Formic Acid at Low Temperatures
H. N. Barham , Louis Watts Clark
J. Am. Chem. Soc., 1951, 73 (10), pp 4638–4640
DOI: 10.1021/ja01154a042


From what i can see it has what you want, but its a pay item over the net. You may be able to get access from your library or university library. This article covers pure and diluted formic acid, and unlike other papers is not concerned with catalysts

 

[itma]

I doubt that any problem would be to do with the chemical breakdown of Formic Acid.


The two problems that I would anticipate with age would be -

1/ Escape of Formic Acid by diffusion through the clear plastic (treatment) packaging. When you open the outer 'tub' you do get a fair whiff of Formic, so the individual packs are not 100% proof.

2/ Ageing of the gel/membrane which holds the acid. This has to release the vapour at the predicted rate, and remain very permeable to allow all the acid to escape from within the gel. Now the gel and its papery wrapper are the "trade secret" parts of the product, so we aren't going to be able to look up papers detailing their change with temperature.



I'd suggest an email to the manufacturers (in Canada) asking how the shelf-life of their product could be extended by the purchaser.
I understand that they have been working to extend the shelf-life, but I don't know whether this is by changing the product formulation or packaging, or simply by proving that it stays 'good' for longer than they first thought.
My expectation would be that (to maintain their approvals) they couldn't change the formulation of the product itself.

 

[masterBK]

I opened a sealed packet of out of date MAQs (5 months past use by date) and noticed that the gel like carrier medium had gone hard and lost its flexibility. Maybe this affects the rate of release of the formic acid vapour.

 

[Amari]

Many thanks folks. Yes I will try and email the manufacturers.

 

[farbee]

I doubt that any problem would be to do with the chemical breakdown of Formic Acid.


The two problems that I would anticipate with age would be -

1/ Escape of Formic Acid by diffusion through the clear plastic (treatment) packaging. When you open the outer 'tub' you do get a fair whiff of Formic, so the individual packs are not 100% proof.

2/ Ageing of the gel/membrane which holds the acid. This has to release the vapour at the predicted rate, and remain very permeable to allow all the acid to escape from within the gel. Now the gel and its papery wrapper are the "trade secret" parts of the product, so we aren't going to be able to look up papers detailing their change with temperature.



I'd suggest an email to the manufacturers (in Canada) asking how the shelf-life of their product could be extended by the purchaser.
I understand that they have been working to extend the shelf-life, but I don't know whether this is by changing the product formulation or packaging, or simply by proving that it stays 'good' for longer than they first thought.
My expectation would be that (to maintain their approvals) they couldn't change the formulation of the product itself.

Formic acid will be stable for years without significant degradation at room temp so at -20oC you are safe.

The gel is polymer whose chemical interaction will quite possibly be affected by freezing/thawing.


I would have stored in 4oC .

I don't know if I would use them; they are really not that expensive to take a risk.

 

[Amari]

I would have stored in 4oC .
I don't know if I would use them; they are really not that expensive to take a risk.

Yes, in retrospect I agree.

 

[Amari]

I have now overcome my laziness and reluctance to go out to the freezer in the garage in the (all day) pouring rain. I found the contact details and have emailed [email protected] the manufacturers for advice and will report back to the forum

 

[Amari]

I have now overcome my laziness and reluctance to go out to the freezer in the garage in the (all day) pouring rain. I found the contact details and have emailed [email protected] the manufacturers for advice and will report back to the forum

At last I've received a reply - not from the above e-address but from [email protected]

Dear Giles,

Thank you for your email, I am glad you liked the article in BeeCraft

Legally, I am not allowed to recommend the use of the strips past the expiry date, but I can tell you that from the experience of my colleagues in Canada, cooling or freezing the strips slows down the degradation process immensely.

You are definitely not endangering your bees by using the strips, except that there is the risk of lower efficacy. I would recommend you to estimate the mite level before and after treatment, using the powdered sugar or alcohol wash method (whichever you prefer).

In our laboratory in Canada, we’ve done some shelf-life tests, of course. Our chemical engineer has told me that what they learned from these tests was basically: The cooler you can store the strips, the better. The shelf-life on the package is given for temperatures <25°C, which can still be quite warm. If you now put the strips in the freezer at -18°C instead, you can imagine that the formic acid in the strips will freeze as well. There is no vapor pressure left under these temperatures that would make the formic acid vaporize as to does under higher temperatures. Thus, it remains in the strips.

I hope my response was helpful, if a bit vague. Please, don’t hesitate to contact me again if you have more questions about how to use MAQS.

All the best,
Ulrike

Conclusion: seems OK to store frozen as per Domino's helpful link above.

 

[itma]

Regarding that communication, the chap thinks solids don't have a vapour pressure. Wrong!
However, in the most general sense, yes, the cooler the storage, the better.


NEVERTHELESS, as recently discussed on this forum, MAQS is an 'approved veterinary medicine' -- and so its use must be recorded (with details of batch number and expiry date) in your legally-required Medicines Record.
Now, I really wouldn't go recording that you have been using Medicines that are past their Use-By dates (regardless of how you claim you have stored them).



/// Incidentally, since the concern seems to be loss of Formic Acid vapour (as I see I suggested previously), leading to loss of product potency ... if it is still going to lose ANY Formic Acid while it is in the freezer, then I'd prefer not to have it in my food freezer ...

 

[jd101k2000]

 

[Erichalfbee]

Thanks Amari.
Your email has confirmed what I suspected.
I have some in the freezer so I needn't waste it.

 

[Amari]

/// Incidentally, since the concern seems to be loss of Formic Acid vapour (as I see I suggested previously), leading to loss of product potency ... if it is still going to lose ANY Formic Acid while it is in the freezer, then I'd prefer not to have it in my food freezer ...

Unlikely because the strips are in a bucket with tight fitting lid. One can be a little too precious at times.

 

[itma]

Unlikely because the strips are in a bucket with tight fitting lid. One can be a little too precious at times.

Formic Acid vapour permeating through the thin plastic pack around each treatment-pair of strips is WHY they are supplied in that thick plastic 'bucket'. (And very useful the buckets are too...)
The bucket retains a lot of the seepage vapour, which is why you get a strong 'whiff' when you open the bucket!
I wouldn't mind having a bucket in the freezer (if only there were room!), but I'd be much less happy about loose pouches ...

 

[einsteinagogo]

At last I've received a reply - not from the above e-address but from [email protected]

Dear Giles,

Thank you for your email, I am glad you liked the article in BeeCraft

Legally, I am not allowed to recommend the use of the strips past the expiry date, but I can tell you that from the experience of my colleagues in Canada, cooling or freezing the strips slows down the degradation process immensely.

You are definitely not endangering your bees by using the strips, except that there is the risk of lower efficacy. I would recommend you to estimate the mite level before and after treatment, using the powdered sugar or alcohol wash method (whichever you prefer).

In our laboratory in Canada, we’ve done some shelf-life tests, of course. Our chemical engineer has told me that what they learned from these tests was basically: The cooler you can store the strips, the better. The shelf-life on the package is given for temperatures <25°C, which can still be quite warm. If you now put the strips in the freezer at -18°C instead, you can imagine that the formic acid in the strips will freeze as well. There is no vapor pressure left under these temperatures that would make the formic acid vaporize as to does under higher temperatures. Thus, it remains in the strips.

I hope my response was helpful, if a bit vague. Please, don’t hesitate to contact me again if you have more questions about how to use MAQS.

All the best,
Ulrike

Conclusion: seems OK to store frozen as per Domino's helpful link above.

for a test, I left a strip in the plastic box, for 12 months, after 12 months, and way past expiry, the strip had turned a brown sugar colour, and it was quite potent, so went in the compost bin, these were stored at approx 15 degree C all year.