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Natural preservation discourse
Had a prospective client ask me yesterday if we would use natural preservatives when formulating their products; they specifically inquired about glucose, glucose oxidase and lactoperoxidase. Here is my exact wording in response:
None
of the materials you inquired about can be considered practical product
preservation agents. Glucose only works when you have a very high
concentration of it (see Brix value) in a formula – honey, molasses and maple
syrup are prime examples of this. As for the other two, you are dealing
with enzymes. These can be reactive with other ingredients, yet also
sensitive to fluctuations of heat and pH for viability, plus are very narrow in
their scope. We use the term broad-spectrum to define an agent capable of
squelching any bacterium specie that may insult the product, plus be able to
defend mold and yeast insults as well. None of those enzymes will do the trick;
you cannot trust them. Plus, you would have to settle for a 6 month shelf-life
if you did. No chemist in the personal care industry with half a brain puts any
measure in these so-called natural preservatives for these - and other –
reasons. I hope this clarifies the matter.I’d like to hear some other opinions on this, if for no other reason that self gratification. -
16 Replies
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Although I am not very well versed with enzyme preservation and all, in fact to be brutally honest this is the first time I heard that glucose might be considered as a preservative no matter what the quantity is. Its a revelation for me, and as for the response I suppose every word that you have penned shouts out so loud and clear that even a layman can feel technical after reading it.
Indeed a great post for late comer like me. -
Hi,
We actually use this preservative system in our super ‘”natural” range. It is a product called Biovert by Lonza.- A two-component protection system
- Mimics a naturally occurring antimicrobial-antioxidant protection system
- Offers broad spectrum activity and reduces risk of oxidative degradation
We also does the product up with rosemary extract and another product called Totarol (made by a local guy in NZ)Totarol™ is a naturally occurring plant extract against potent anti-bacterial activity in both gram positive and gram negative bacteria. Totarol™ has also potent anti-oxidant properties. Totarol™ is active against acne and tooth decay bacteria, and is one of the rare phytochemicals active against penicillin and methicillin resistant strains of Staphylococcus aureus.We give the product a shelf life of three years and it is all sold in tubes which are air tight. We have not had any issues with micro to date. Our range can be seen online: http://www.tiakiskincare.com/ As a side note the range is a beige colour due to the rosemary extract and has a distinct earthy/plant fragrance. -
I am assuming that the Totarol is the same as Biovert;
http://www.lonza.com/products-services/consumer-care/personal-care/search-by-brand/biovert.aspx
http://www.cosmeticingredients.co.uk/ingredient/biovert%E2%84%A2They even use the same exact verbiage.
The INCI is Glucose & Glucose Oxidase & Lactoperoxidase. It is a 2 part system that works fairly well. I used it several years ago as it is hardly new.
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Hi Mark,
The totarol is quite different to the biovert. It is an extract form the totara tree here in NZ. The INCI is:Not sure why we use both systems - the formulation predates me.CheersSarah I see that I missed that on my first read through.
I get approached to use new “natural” preservatives all the time. My rule is that I will use it if there is enough manufacturer guidance for the Formulator AND I will insist on Challenge testing.
Keep in mind that we do fixate on the preservative and miss the overall picture. Preservation is also a matter of using hurdle technology; pH adjustment, proper packaging, adding a chelant, possibly adding a glycol to boost the system (look to Schulke on that one) and maybe using an Essential oil to AUGMENT the preservation system. It really takes a big picture approach. In the end Challenge Testing will either validate or invalidate your system.
Am I correct in thinking that this Totarol is an essential oil similar to Neem, Tea Tree … ?
I did a little research and the described properties sound similar.Annoyingly, it is hard to find MIC comparisons because people have tested them against quite a lot of organisms but not on both. MIC in microgm/mLI decided to see if I could compare tea tree oil with Totarol. A few matches:Organism . . . . . . . . . . . . . . . . . . . . . . . MIC(tto) MIC (Trl)Enterococcus faecalis . . . . . . . . . . . . . 0.5-0.8 2Klebsiella pneumoniae . . . . . . . . . . . . 0.25-0.3 >32P. Acnes . . . . . . . . . . . . . . . . . . . . . . 0.05-0.6 3.9Staph. Aureus . . . . . . . . . . . . . . . . . . 0.5-1.25 1.5The MIC is the minimum concentration required to stop growth in 24 hours. From the data above and other data I Googled, it appears to me that TTO has a higher antibacterial activity than Totarol. Of course there are many other factors to consider such as odour, solubility, dispersability, ability to destabilse emulsions or gels, etc etc etc.I am occasionally tempted to try systems such as (eg) TTO, Propiolis, etc. along with the usual precautions ably mentioned by @Microformulation. But then I glance over to the long term test shelf where products sit that are over 4 years old, and still in clean condition, and think… no. @belassi I agree with being wedded to the older tried and true preservative systems. Heresy of all heresies I still think parabens were outstanding options. However with market demands we are seeing more and more accounts lead with “natural.” As well they are well versed in the scaremongering. Occasionally we will get great pressure to use a “natural” preservative. In that case challenge testing is the way to go. If they balk at the price I will ask them to sign a waiver. The waiver usually inspires them to re-evaluate the overall Formulation.
My current systems are:
Skin creams (o/w emulsions): 0.5% parabens, made up of 60/40 methyl/propyl. Never had an issue.Skin gels (oil free): Spectrastat at 0.7%. Seems pretty effective although we have only been using this about 6 months so far.Shampoo: 0.5% potassium sorbate and pH = 5. No issues, works fine.Conditioner: 0.5% potassium sorbate, pH = 5. I have to say that a shelf life of around 6 months with this, due no doubt to the relatively large amount of lipids. I am considering what to do to improve shelf life. Yes totally agreed Mark, there’s a lot more to effective preservation than just added a preservative and hoping it will do the job. In a different thread in this forum I posted this checklist which might prove useful for any newbies reading this thread:-
1. Minimise sources of energy for microbial growth (aka “bug food”) - eg fruit, botanicals, tea, lecithin, mineral water, milk of any kind, honey, hydrosols, floral waters, aloe vera, extracts, protein, clay, powders, starches etc - reduce these to a tiny %.2. Double check against this webpage whether your preservative is truly broad spectrum -http://makingskincare.com/preservatives/3. Add glycerin and other polyols4. Add 0.2% disodium EDTA into the heated water phase5. Switch to packaging which the customer can’t contaminate easily - jars are the worst for contamination.6. Reduce the pH to between 4 and 5 if possible.7. Sanitise your equipment with 70% IPA8. Use distilled, deionised or purified water, not tap/faucet or mineral water9. If your water isn’t micro checked, heat and hold your water phase at 75c/167f for 20 minutes - this will kill some of the non-endospore forming bacteria. (If your preservative can withstand heat put it in the heated water phase rather than the heated oil phase. This improves preservative contact with the water phase so that it is not partitioned in the water-oil interface).10. If possible micro test all of your raw materials.11. Use good GMP - http://www.mariegale.com/good-manufacturing-practices/gmp-basics.html12. Don’t rely on sight, smell - one can put 100,000 bacteria into a milliliter of water and the water will appear to the naked eye to be crystal clear and usually won’t smell bad. Most cosmetics tested have counts ranging into the tens of thousands or millions of cells per milliliter have subtle or no aesthetic differences from sterile samples. The only way to know if your preservative system is working is to get it tested. To Sarah: I realize you do have a full brain, so please excuse my ratty comment in the original post. That you’ve used that Lonza Biovert with no difficulty is as much a testament to your good GMP as it is to your preservative selection. I’ve read Lonza’s literature and I find it underwhelming. That product relies on redox processes, and it’s activity can be imperiled by so many ingredients, including ones mentioned or alluded to by Making and Mark. Regarding Mark’s comment,Sarah, have the results of your USP Preservative Challenge been acceptable, and did you retry that challenge on the same lot 12 months later? I’d be curious.
To all: thanks for the feedback. You all make a compelling argument that a holistic approach to formulating must be employed when using any preservative that does not use blunt cell-disruption chemistry, like my friends the parabens, phenolics and formaldehyde donors do Regarding point #11 in Making’s exhaustive list: Dave Steinberg once said the best preservative of all is strict GMP.There’s enough material here to draft an interesting article in C&T or SPC. Anyone game? Or maybe an article for the Chemists Corner blog! ;
I am sure it would make a great article. I find so many beginning formulators spending their whole time trying to find the “perfect” preservative and missing the big picture. If only it wer as simple as adding the preservative and mixing until homogenous.
@Matt, I have had the product tested at 6,12 and 36 months with no issue. As I mentioned we also use Totarol and the product is packaged in tubes with a pump which does not allow any air to seep back in. We use loads of ethanol to sanitise everything during manufacture and to be honest I think that we have just been lucky.
I have not used this preservative system in any projects which I have been responsible for - I use Geoguard ECT which is ecocert so acceptable to the Marketing department. This discussion and a few articles I recently read prompted me to write the following post about preservatives. What do you think?
Great article. I like the stance to stand firm against Marketers demanding riskier preservatives. Pragmatically I see too many companies where the Formulator is not given this option and Marketing wins out more often than not.
Indeed, marketing does have a lot of sway in the way things are done in the cosmetic industry.
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