The_Microbiologist
Forum Replies Created
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Wow there is a lot of misinformation in that segment for how short it is. I would have expected a lot better from the Discovery Channel.
First, we don’t “…all know that hand sanitizer is bad for you.” The last time I checked it was great for killing pathogenic bacteria on hands when soap and water isn’t available. I’ll take a little BPA over some O157:H7 E. coli any day.
Second, the active ingredient in hand sanitizers is usually ethanol, sometimes quaternary ammoniums, but hardly ever Triclosan. It is pretty obvious that she has hand sanitizer confused with antibacterial hand soap for consumers (which is essentially dead as a category now thanks to recent - and appropriate - FDA action).
Third, it’s not like Triclosan kills good bacteria but leaves antibiotic resistant bacteria alone. It kills both categories equally and therefore doesn’t select for one over the other. If one were to use “Triclosan Hand Soap” their hands wouldn’t be crawling with MRSA 5 minutes later or a month later, for that matter.
What a joke that clip was. It’s a shame it’s passed off as scientific news.
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We run CTFA M-6 for atypical cosmetics. There is some info on the linked page.
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Hi Everybody - nice discussion. Antimicrobial is my game, so allow me to opine
There is a whole spectrum of activity that falls under the term “antimicrobial,” from preservatives that exert growth-inhibiting effects slowly over time to potent disinfectants that literally break cells apart within just a few minutes.
In the context of hands, contact times are on the order of seconds so a very potent, but very skin-safe antimicrobial would be needed to realize any appreciable biocidal effect.
There are only two actives that fit that bill: ethanol at >60% and quaternary ammoniums. Both are problematic to formulate into soaps.
Note that FDA now requires clinical studies showing effectiveness for consumer antibacterial soaps, which effectively killed the whole category.
Natural ingredients and the ingredients discussed above are just not powerful enough to make much of a dent in that short period of contact time.
Thus, in my view, those interested in hand hygiene should focus on building soaps with excellent detergent/cleaning properties that promote frequent use by being easy on skin, having great texture, and smelling great; essentially shift the goal to handwash frequency and germ removal rather than germ killing.
Microbial removal from handwashing can be studied pretty easily on volunteers, so it can be a substantiable (is that a word?) claim.
Just my thoughts
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Hello,
Yes, it is possible to formulate such a hand soap, but it will require so much lactic acid that it will smell bad. On the regulatory side of things “antibacterial hand soap” is a drug. Lactic acid is not (as I recall) a listed active ingredient on FDA’s tentative final monograph for antiseptic drug products, so technically a new drug application would be required. That would cost a lot of money and take a lot of time.
Good luck!
Ben
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Hi Everybody,
This may be informative. I am pasting it from Antimicrobial Test Laboratories’ newsletter from June. That lab is my “main” one:
Background: On December 16, 2013, FDA proposed a ban on antibacterial consumer hand soaps, questioning
effectiveness relative to ordinary soaps and expressing concern that
“…exposure to certain active ingredients in these products could pose
health risks such as bacterial resistance or hormonal effects.” FDA gave manufacturers 6 months to comment on the proposed ban and 1 year to provide clinical studies showing effectiveness.
Current Events: In response, the American Cleaning Institute and Personal Care Products Council filed extensive comments on the rule and funded a new, non-clinical study showing effectiveness.
In that study (which appears to have lacked critical
neutralization-verification controls, critical for chlorhexidine and
triclosan), liberal use of antibacterial soap appeared to kill 90-99%
more bacteria on hands than ordinary soap. Finalization of the new rules
is expected after December 16, 2014. -
This is the million (billion?) dollar question! If any of you out there ever come up with a safe, all natural cosmetic preservative that works as well as the old standby preservatives (parabens, etc) when in a complete formulation then please do get in touch with me. We will have a business to make together
cossci21: Organic acids, leucidal, and potassium sorbate/benzoate are pretty much all that come to mind and in my view all have ample disadvantages compared to traditional preservatives.
Good luck!
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He ELDEskin,
Well, you asked
I think you’re playing with fire. Here’s why: Many common preservatives are incompatible with certain other formula ingredients, and it’s often surprising which combinations “knock out” the preservative activity. Without testing, you’ll never know whether or not that is happening in your formulation.
Also, typical micro QA is not sufficient to indicate a product is well preserved because micro QA is typically done right after production, before bacteria and fungi have a chance to get a toehold and begin reproducing. It is also possible that your production to date has been unusually hygienic or that by luck it hasn’t introduced too broad a range of microorganisms (each one bringing its own set of tools to feed on the product).
I think you should run a simple challenge test on the formulation (preferably at a good, specialized microbiology lab). Challenge tests like USP 51 use a broad array of microorganisms introduced to the sample in great numbers. 95% of the time, they’ll pick out formulations that are not biologically stable. To pick out bad formulations 100% of the time, manufacturers make them even more challenging with repeat inoculations, an additional set of microbes, diluting the product before the test, etc.
If you do not run a challenge test there is a risk - and we don’t know how great - that the product will support microbial growth. That will result in spoiled product at a minimum and health risks as a worst case outcome.
One last thought - most microorganisms of concern in cosmetics grow fairly well in anaerobic (air free) environments, so the airless packaging helps to control contamination but can’t be counted on to prevent it entirely.
Good luck!
Ben
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Just so the gang that frequents this forum knows, it only takes one microorganism to completely contaminate and ruin an unpreserved, previously sterile cosmetic product or raw material, if that substance supports microbial growth. Keeping something sterile requires good knowledge of microbiology/aseptic technique and a sterile work environment of some sort such as a laminar flow hood or biological safety cabinet. In other words, it’s not practical for most non-pharma companies!
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Perry’s right. If a raw material is unpreserved and not well known by formulators/suppliers be inherently resistant to microbial contamination, then it’s probably contaminated or at least risky. Certainly if it contains water and has a pH between about 5 and 10, then it should be preserved.
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Hi Vjay,
If a surfactant contains 50-70% water it should be tested for bacteria/fungi. If it contains 30-50% water it is less likely to be contaminated, but if it were my cosmetic line, I would still want it tested.
Many companies add preservatives to their surfactant blends.
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Milliachemist - great comment, made me laugh out loud
Bobzchemist - interesting find. Antimicrobial agents often have synergistic effects…perhaps this is PG’s way of taking full advantage of that as a way to save on cost of preservatives?
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Perry I agree. Typically the bigger companies know the risks micro poses well enough that they do adequate microbiological stability testing of their formulations. I think that perhaps this one fell through the cracks because they acquired the company (and the formulation) recently.
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Hi Eli,
Microbes are notorious for propagating from seemingly out of nowhere…when you have liquid around nutrients, you can count on them showing up at the party.
In fact, they pop up so quickly and reliably that people literally used to think that they spontaneously generated (appeared from nothing).
I’m glad my comment was helpful.
Ben
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Hi Eli,
Yes, microbes will definitely cause loss of optical transmittance in a water based solution. In fact, we use spectrophotometers to quickly estimate microbial concentrations in broth cultures. Each little cell is sort of like a glass sphere when it comes to light, they cause the light to refract and go in all different directions, which means it doesn’t wind up at the sensor (that is, it’s not “transmitted”)
To answer your second question, I would have to know which microbes you’re using and specifically what you’re doing (what temperature, humidity, vessel type, etc).
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I think that Sarati Private Label might be your best bet. They’re in South Texas and I toured their facility once. I got the impression that they do some pretty small projects (as well as lots of larger ones). I’d give them a call.
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Wow, the pictures really help! What you are considering to be “confluent growth” I think is probably more along the lines of a “spreader,” meaning a single or a few colonies that rapidly take over the plate either by rapid multiplication (which gram+ rods are great at) or other means. The way you can check this is to look at the plate after just 12 or 18 hours incubation, then again at the end of the incubation period. My guess is that you will have one or a few colonies only to begin with, then a couple of days later I imagine those colonies will have spread over the entire plate. Do note the zones that on the plates in question that do not show growth. If the product was very contaminated and the spread plating covered that part of the plate, I would expect growth there.
The other explanation is that the plates are too wet, so you have a situation where microorganisms grow in the fluid on the surface (as if growing in broth) and then that fluid gets spread around the plate during movement and seeds other parts of the plate.
There is no need to send anything out to get it ID’d at this point. For practical purposes if you can’t tell them apart on the basis of colony morphology, you can consider them the same organism.
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Welcome to the forum!
Are the colonies that always appear on your plates the same type type, or do they vary? Do they “run with the dilutions” meaning that there are more contaminants in plates that got more neutralized product and fewer in plates that got less? If you haven’t done a dilution series it’s easy, just put 1/10 of what you would normally put onto a plate onto an agar plate and incubate, then compare with the ordinary plate.
If the contaminants “run with dilution” that’s a good indication they’re actually in the product (though it may also indicate they’re in your neutralization medium) and you’re just detecting them where other labs are missing them. There are all sorts of ways labs miss contaminants….no/poor neutralization of preservatives, too high of incubation temps, not long enough duration of incubation, etc.
If the colonies appear on every plate regardless of dilution and especially if they’re morphologically varied, then you probably have some sort of lab contamination going on and the product is in fact clean. The contamination could be from air, technique in need of improvement, or even non-sterile plasticware marketed as sterile. It happens. Part of the art of microbiology is reducing the frequency with which such contaminants pop up and learning to tell environmental contaminants from product contaminants.
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Hi Shepard,
D/E broth has more neutralizing chemicals, by mass and number, than ordinary Letheen broth. For instance, it has 10X the lecithin. In my experience, that makes it better for emulsification of oils or oily test materials. Plus I imagine there are all sorts of trace chemicals in petrolatum that could be toxic to bacteria. D/E broth has sodium thiosulfate, sodium bisulfate, and some other goodies in there that may neutralize them and that will increase the odds that our friend Adam will pass his suitability/recovery validation test.
Ben
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Also you might check out this CTFA test method for some tips on how to recover microorganisms from oil-based test samples.
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Hi Adam,
I suspect your concern is getting microbes in the petrolatum to mix with water in order to be present and uniformly distributed in the solution used for dilution and plating.
I imagine you could use an ordinary APC procedure (1 gram product into 9 mL D/E broth, vortex mix, then plate, then incubate), but you would have to validate recovery using a procedure similar to that laid out in USP <61>.
The duration (>1 min) and temperature (I suggest 35C) of the mixing step will be important. Also, I am specifically recommending D/E broth over letheen, etc.
If recovery verification fails, then try a greater dilution (say 1 ml in 99 ml D/E broth). If that approach is not suitable either, then re-post and I can share some “advanced” techniques.
Good luck!
Ben
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Thank you all for the kind comments!!!!
I’m on the forum to help as much as I can and if my lab can assist with testing that’s great too.
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Fundamentally, UV-C technology is great for knocking down levels of
problematic germs in the environment when people aren’t present in the room. Labs have used UV to decontaminate containment hoods for decades and several companies now use large
UV systems on wheels to decontaminate hospital rooms.A high-output germicidal UV light might be helpful in your case, but a small one probably wouldn’t help much. Effectiveness is a function of the number of photons at the proper
wavelength that are delivered to the target organisms, so in this case
size mattersNote that the same thing the UV does to the DNA of microbes to kill them (destroy/mutate the DNA by causing thymine and cytosine bases to dimerize or pair together) happens the same way to human DNA in skin and eye cells, so PPE would be crucial!
From the standpoint of practicality I’d skip it and perfect your ordinary facility hygiene practices instead. Good question, though. Thanks for asking.
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I agree with Perry’s “better safe than sorry” approach.
I recommend running the challenge test on the intact formula, using approaches laid out in CTFA M-6. Depending on oil/water content the approaches vary, but the idea is to modify the inoculum by diluting it in light mineral oil or emulsifying it, then introducing it to the product. I don’t think most contract labs run that method, so I’ll tell you that Cosmetic Test Labs does just as FYI.
Good luck!
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Hi Bati,
Preservative challenge tests for wipes are definitely more challenging than similar tests for liquid products. Most of the large companies that make wet wipes have developed customized challenge test protocols, but they usually go something like this:
The company delivers several sets of wet wipes to the lab in sealed baggies, having same wipe/liquid ratio that will be used in the final packaging. Then the lab inoculates stacks of wipes separately for each microorganism and contact time, typically by inserting a micropipette tip into the middle of the stack (in between wipes) and delivering the inoculum.
Then the lab counts the initial microbial population and eventually the final microbial population by transferring the wipes to a large volume of neutralizing solution, such as 100 ml of D/E broth, mixing thoroughly to remove microbes from the wipes, then counting the number of surviving microbes in the fluid and back-calculating to CFU/wipe.
One of the things that makes wet wipes more difficult to preserve is cellulose-based substrates, which are great food for fungi and wipe/liquid interactions which sometimes reduce levels of free, available preservative in the liquid over time (presumably by weak binding of the preservative to the substrate, which takes the preservative out of the picture as far as germs are concerned).
Let me know if you have any more questions.
- Ben
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Another option would be to get a time machine, then go well into the future and see if the product is germy.
Unfortunately my time machine seems to be broken. I can only get it to go forward at normal speed.
