Microbiological growth in rinse off products.

Greetings to forum members.

My query is related to the microbiological growth in rinse off products. What could be the possible sources for the contamination of the product with the following bacteria.
1. Pseudomonas Stutzeri
2. Aeromonas Salmonicida
3. Non-fermenter spp.

What are the solutions to prevent such microbiological growth in any rinse off products such as hand soap ?


 

Comments

  • Try with formaldehyde releaser such DMDM Hydantoin,  imidazolidinyl urea, etc. They effective and safe for rinse off products
  • PhilGeisPhilGeis Member, Professional formulator
    Try with formaldehyde releaser such DMDM Hydantoin,  imidazolidinyl urea, etc. They effective and safe for rinse off products
    Good ones above but recommend as best Na benzoate/chloromethyl isothiazolinone /EDTA.
    However these are manufacturing contaminants - appears you need major improvement in manufacturing hygiene and GMP's.  Preservatives are largely intended to protect during consumer use.
  • ozgirlozgirl Member, PCF student
    I would check your raw materials to ensure that they are not the source of contamination.
  • All good points so far- What preservative are you currently using and what is your water source?


  • @ozgirl the raw materials are surfactants like sodium laureth sulfate, cocamidopropyl betaine and linear alkylbenzene sulfonic acid; rheology modifiers like sodium chloride, fragrances, colorants.

    @EVchem currently I am using tap water and Proxel 106 as a preservative.

    Is water the primary bacterial source ???
    Is a robust preservation system not sufficient to prevent microbiological growth ??? 
  • Proxel 106 already robust preservation, are you used based on recomendation? 0.1-0.3% (1-3 ml/ kg product)?
  • Bill_TogeBill_Toge Member, Professional Chemist
    tap water is not sterile - depending where it's sourced from, and the ambient temperature, it can be crawling with microbes
    UK based former cosmetic chemist with 13 years' experience at the bench. I've worked with pretty much everything apart from pressed powders, soap, solid lipstick and aerosols. Now working in the messy world of screen-printing inks.
  • definitely agree with bill- tap water introduces huge potential burden, you can test it to confirm but ultimately for consistency you should get DI water at least
  • Which microbiological tests are recommended for the tap water which I am using ???

    I have come across total plate count test but there may be other more reliable and accurate tests. Please provide your valuable insight on this issue. 
  • Ditch the tap water. 
  • Is proxel 106 a suitable preservative to be used for hand soaps ??? 
  • What is the composition
  • PhilGeisPhilGeis Member, Professional formulator
    edited October 2021
    Is proxel 106 a suitable preservative to be used for hand soaps ??? 
    No.    It's formaldehyde with CMIT/MIT.  The formaldehyde is not needed - as it shares efficacy with CMIT.  It's intended for paints coatings etc. where manufacturing contamination is typically pretty bad and the two strong preservatives help against resistance development..  Think some folks consider formaldehyde presence in head space in can discourages mold.
  • What are the recommended preservatives then especially for rinse off products ???
  • PhilGeisPhilGeis Member, Professional formulator
    Suggest CMIT/ Na benzoate /EDTA unless you formulate to be politically-correct.  Good luck with that.
  • Is Biocrol WS1 from CISME Italy a good option for preservative ???
  • PhilGeisPhilGeis Member, Professional formulator
    edited October 2021
    it's CMIT - keep it less than 5 ppm active and combine with Nabenzoate and EDTA
  • Why is there a need to combine CMIT with sodium benzoate and EDTA ???

    Is Biocrol WS1 alone at the dosage of 0.15% w/v not sufficient to inhibit microbiological growth in rinse off products ??? 
  • PhilGeisPhilGeis Member, Professional formulator
    Na benzoate broadens the spectrum and EDTA complexes divalent cations, esp. Ca++ to destabilize biofilm/capsule..  CMIT is primarily effective vs Gram negative - Na benzoate in surfactant context increases efficacy and broadens spectrum.  Two preservatives should make it  ore difficult for the microbes to adapt.
  • Sodium benzoate's activity is very low at pH above 5 and liquid hand soaps usually have pH ranging from 5.5-7.5.
  • Is Lonzaserve ID a better option for rinse off products ???
  • PhilGeisPhilGeis Member, Professional formulator
    Sodium benzoate's activity is very low at pH above 5 and liquid hand soaps usually have pH ranging from 5.5-7.5.
    Re. Na benzoate, In presence of  some surfactants, the pKa is effectively increased.  I've found effect at 7 .   Please look at labels - CMIT/Na Benzoate is in Head & Shoulders, Pantene, Herbal essences, Aussie - all pH well above pKa.

    Lonzaserve ID is a combination of DMDM Hydantoin and CMIT - very effective but prob overkill as they share the same primary spectrum of efficacy tho discouraging adaptation.  might be advisable if you've a resistant bug in your manufacturing system.
  • What would be better to use Biocrol WS1 or Lonzaserve ID ???
  • PhilGeisPhilGeis Member, Professional formulator
    With the contamination you mentioned, probably the latter with EDTA.  Your primary fix must be in bringing GMP's, manufacturing hygiene and possible biofilm into control..
  • What form of EDTA should be used ??? Is it tetrasodium EDTA solution ???
  • PhilGeisPhilGeis Member, Professional formulator
    what goes into solution
  • AbdullahAbdullah Member
    edited January 2022
    PhilGeis said:
    Is proxel 106 a suitable preservative to be used for hand soaps ??? 
    No.    It's formaldehyde with CMIT/MIT.  The formaldehyde is not needed - as it shares efficacy with CMIT.  It's intended for paints coatings etc. where manufacturing contamination is typically pretty bad and the two strong preservatives help against resistance development..  Think some folks consider formaldehyde presence in head space in can discourages mold.
    Do you know the percentage of formaldehyde and CMIT/MIT in proxel 106? @PhilGeis
  • PhilGeisPhilGeis Member, Professional formulator
    Couldn't find it - but should be on its MSDS.
  • PhilGeis said:
    Couldn't find it - but should be on its MSDS.
    Thanks
Sign In or Register to comment.