Need help with preservatives

markbroussard

Member

January 6, 2019 at 11:49 pm

Nonsense … Schuelke is the leading microbial testing company in Europe and these tests are used extensively in a wide variety of industrial applications. It’s nothing more than an agar growth medium which is commonly used in micro labs for plate tests. If you fail a dipstick test, there is no way you are going to pass a PCT, so they are reliable screening tests. In fact, if you have any growth at all on a dipstick test, then you know for certain that your preservative system is not working.

Now, I don’t know about the quality of dipsticks from Lotioncrafter, but no reason why those would not work the same … in fact, they may well buy them from Schulke and repackage them.

If you are a homecrafter and you are relying on nothing more than looking at your samples to see if you can detect microbial growth, you have absolutely no clue whether your concoctions are adequately preserved or not.

ngarayeva001

Member

January 7, 2019 at 12:03 am

I don’t have an idea if something is preserved, but if I see a mold on the surface I clearly know it’s not. That was the reason why I brought up my experience with Euxyl. If not sure add parabens. If someone has a chance to send a sample for a test multiple times, it’s definitely better to do it.

markbroussard

Member

January 7, 2019 at 12:24 am

You should not rely on “add parabens” as if that was a cure-all for preservation.

Every formula is different and the preservation strategy that works for one formula may not work for another similar formula. The only way to know is to test.

It’s simple … if you don’t test, you don’t know. Unless, of course, you can see mold growth, but the real issue is just what is it that you can’t see growing in your sample?

There is no need to “send a sample for a test mulitple times” … simply use a dipstick for a scoping confirmation on preservation. Again, since you’re a homecrafter who is not making commercial products, that’s all you need if you want some modicum of certainty.

doreen

Member

January 7, 2019 at 11:35 am

@ngarayeva001
There is nothing wrong with the slides from Lotioncrafter I think, it’s that some people believe that only Preservative Challenge Tests are useful.
A slide or plate test of course only tells you that there is contamination by bacteria, yeast or fungi, it doesn’t tell you the species. Sometimes it’s obvious, but many times it isn’t. (To me at least, as I’m not a microbiologist.) So you won’t know if the microbe growing on the plate is a pathogen or not.

I understand the people who believe that, but personally I still find the plates useful. If there is no contamination it assures me that the batch is ok, if there is, I just throw it away. You only need a bit of patience to wait before you can use that what you have just made.

I don’t know about the slides, but the plates get contaminated very quickly, which has been a reason that a type of plate we used at work to test surfaces was ‘double sterilized’. This meant that not only the plates are sterilized, but also the primary packaging material around it. It was more expensive, but finally we had no more contamination of the unused plates (also no more condensated water in it). Before that we were in doubt if the contamination came from anything else than the subject we had tested.

@MarkBroussard
I agree with you that contamination rarely comes from particles in the air and that you want to test real life situations.
The point I tried to make was, that if you would test your concoction in a ‘dirty’ environment, you might not know if the contamination came from the environment or from your product.
But you’re right, no matter the source, any contamination would point out that the way the product is preserved isn’t adequate or else the microbes would have been eradicated by it. Thanks for reminding me of that.

markbroussard

Member

January 7, 2019 at 12:32 pm

@Doreen:

Yes, if you have any microbial growth in a product it fails … it does not matter if the organism is pathogenic or not, you simply fail because your preservative is not preventing all microbial growth.

Yes, you want to use GMP in making your batches, but once the product is being used by a a consumer, it will be exposed to the untreated ambient air and their fingers … so these are the real world conditions under which your preservative must be effective.

Now, if you are a manufacturer making a number of products for different customers, any extraneous source of microbial contamination will affect all of your production, so it will make sense to install UV lamps in your facility and in the HVAC system.

Ahmad

Member

January 30, 2019 at 10:03 am

Hello everyone; just out of curiosity i want to know use of Formalin as preservative?
is there any limit of its use now?
In our country its still being used by the local manufacturers.

belassi

Member

January 30, 2019 at 7:23 pm

NOT permitted.

Ahmad

Member

January 31, 2019 at 7:15 am

@Belassi
many thanx

abdullah

Member

November 30, 2021 at 12:26 pm

Perry said:

Well, that depends on what else is in your formula. But DMDM is safe for use up to 1%.

Of course, you have to do a preservative efficacy test to determine whether your formula is safe when using only DMDM Hydantoin.

@p@Perry ca i ask is the upper limit of DMDM hydantoin 1% or 0.6%?

oldperry

Member

November 30, 2021 at 2:21 pm

@Abdullah - It’s 0.6% in the EU and 0.3% in Japan.
I said 1% because DMDM Hydantoin is sold as a 55% solution. So, if you use 1% of that in a formula, you would be at 0.55%.

abdullah

Member

December 1, 2021 at 1:16 am

Perry said:

@Abdullah - It’s 0.6% in the EU and 0.3% in Japan.
I said 1% because DMDM Hydantoin is sold as a 55% solution. So, if you use 1% of that in a formula, you would be at 0.55%.

Until now i was thinking upper limit is 0.6% solution, not the actual product.

Thanks for the information.