Home Cosmetic Science Talk Formulating Does this formula need preservative?

  • Does this formula need preservative?

    Posted by abdullah on February 10, 2021 at 2:58 pm

    This is a hard surface bathroom cleaner. Does it need a preservative at acidic pH 5 or 6 and alkaline pH 11 or 12?

    Ingredients
    Tetrasodium EDTA    %2
    Surfactant SLES or LABSA or APG %2
    NOAH to adjust pH
    Water 

    PhilGeis replied 3 years ago 4 Members · 10 Replies
  • 10 Replies
  • paprik

    Member
    February 10, 2021 at 6:43 pm

    Yes, it does. Anything above  pH 3 and lower then pH 10 and including more than 5% of water needs to be well preserved. 
    Otherwise micro-organism will start to grow and will spoil your product or you would be cleaning surfaces with bacteria, mold and yeast “infused” product. That would be lovely, aye? :) 

  • pharma

    Member
    February 10, 2021 at 8:33 pm

    Paprik said:

    ….or you would be cleaning surfaces with bacteria, mold and yeast “infused” product. That would be lovely, aye? :) 

    It’s called EM (effective microorganisms) and they are THE hype in eco-friendly cleaning and sell for way more $$ than traditional cleaning products no matter their effectiveness! I’d recommend something based on lactic acid bacteria (LAB is another great sales pitch) ;) .

  • paprik

    Member
    February 11, 2021 at 12:17 am

    Pharma said:

    Paprik said:

    ….or you would be cleaning surfaces with bacteria, mold and yeast “infused” product. That would be lovely, aye? :) 

    It’s called EM (effective microorganisms) and they are THE hype in eco-friendly cleaning and sell for way more $$ than traditional cleaning products no matter their effectiveness! I’d recommend something based on lactic acid bacteria (LAB is another great sales pitch) ;) .

    Hello Pharma, 
    I don’t know who you are, but your comments are legend! :) I always learn something new from you. Thank you :) 
    I haven’t heard about this trend, but … yeah, sounds ridiculous.

  • abdullah

    Member
    February 11, 2021 at 1:56 am

    @Paprik 
    You mean at pH 5 or 6 it needs preservative and at pH 11 or 12 it doesn’t?

    As this product will not be in contact with human skin i want it to be as inexpensive as possible. 

  • abdullah

    Member
    February 11, 2021 at 2:00 am

    Pharma said:

    Paprik said:

    ….or you would be cleaning surfaces with bacteria, mold and yeast “infused” product. That would be lovely, aye? :) 

    It’s called EM (effective microorganisms) and they are THE hype in eco-friendly cleaning and sell for way more $$ than traditional cleaning products no matter their effectiveness! I’d recommend something based on lactic acid bacteria (LAB is another great sales pitch) ;) .

    I didn’t get this lactic acid bacteria thing. Can you do some more explanation please

  • PhilGeis

    Member
    February 11, 2021 at 2:43 pm

    Agree - ecofriendly is advertising hype in any context.   
    Have you sen any data for the “effective  microorganisms”?  I’ve seen it hyped on facebook  but the marketer didn’t offer any meaningful efficacy data.  
    A major concern they blow off is safety - spraying bacteria, fungi and their alleged enzymes in the beathing space is risk for sensitization.

  • pharma

    Member
    February 11, 2021 at 6:32 pm
    The safe thing about many EM products is that they contain most likely no living organisms, just fermented ‘soup’ and residual enzyme activity.
    The nice thing when using lactic acid bacteria as EM is that LAB are usually not pathogenic, do not produce toxins, do not produce smelly metabolites, are easy to cultivate also in a selective way even in the kitchen, lower pH by producing lactic acid (helps removing scale and ‘inactivates’ ammonia and related products -> useful to clean dog/cat piss), and last but not least are very trendy (probiotics). The products I’ve tried were okayish, actually better than I expected… like using diluted acid and soap water though didn’t quite work as advertised for dog pee odour.
  • PhilGeis

    Member
    February 12, 2021 at 10:04 am

    Pharma - assumptions/advertising -  the stuff hasn’t been shown to be “safe” or nice. Enzyme sensitization on inhalation is not uncommon.  One major marketer experimented tried protease enzymes in a bar soap context and ran into significant and serious allergenic response.   They’ve found even worse problems in manufacturing laundry detergents with enzymes.  Folks may also respond to the lactobacilli themsleves but, unwittingly those folks may have mitigated as lactobacilli in some context mitigate immune response.

    Are you aware of data fom those folks re. your imagined efficacy scenario?

    Also be aware that lactobacilli can carry markers for antibiotic resistance.  Unlikely to be medically signficant themselves, they could be a source for horizontal gene transfer.

  • abdullah

    Member
    February 12, 2021 at 1:59 pm

    Thank you all. 
    @PhilGeis @Pharma @Paprik 

    By the way. Is %2 tetrasodium EDTA enough for this purpose? 

    If we use sodium citrate instead of EDTA, what percentage of citrate functions equal to %2 EDTA? As citrate is 1/5 the price.

    Can we use sodium citrate in pH 11-12?

  • PhilGeis

    Member
    February 13, 2021 at 11:25 am

    Good point - back to your original question.    At pH 11-12 you need no preservative.
    2%  EDTA is well beyond the preservative aduvant level (~0.1%).  In that context, citric acid is not as effective as EDTA and, at alkaline pH, will be its sodium salt.    

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