Does 20% sodium chloride in water need preservative?

I usually make 20% sodium chloride in water in 180kg size and store it and use it in shampoo. So do i need to add preservative to this solution when i am storing it? 

Comments

  • PhilGeisPhilGeis Member, Professional formulator
    20% is not prohibitive to microbial growth.
  • PharmaPharma Member, Pharmacist
    +20% salt only allows growth of extreme halotolerant and extreme halophilic microbes (CLICK) which are usually only found in environments naturally very high in salt. Hence, there is a very high chance that you won't have microbial growth (however, 20% salt doesn't mean contaminating microbes will die in there) especially if you were to cool your batch or boil it before 'canning'.
  • PhilGeisPhilGeis Member, Professional formulator
    Moderate halophiles can grow up to 20% salt and halophiles are among the contaminants of many household and industrial products - minerals/salts themselves are often the source.
    Pharma makes a good point - they are heat sensitive.  Boil it and seal it - or take your chances.
  • PharmaPharma Member, Pharmacist
    PhilGeis said:
    ...are among the contaminants of many household and industrial products - minerals/salts themselves are often the source...
    Good you mention this, it completely skipped my mind. Totally makes sense especially regarding sea salt. Saline lakes and salt evaporation ponds are home to a plethora of 'weird' microbes such as halobacteria (hence the red colours) which aren't found elsewhere... as it seems with the exception of the unsuspicious salt shaker in everyones kitchen. Hmm... in hindsight it sounds so obvious (*feeling stupid right now*).
  • PhilGeisPhilGeis Member, Professional formulator
    Pharma - and worse - the damned things are so hard to culture, it takes forever to figure out the problem (discolor, clouding, slime) is microbial. 
  • @Pharma @PhilGeis then what percentage of salt is prohibitive to microbial growth?

    Also does 35 g/100 ml solubility mean 35%?
  • PhilGeisPhilGeis Member, Professional formulator
    Not sure there is a limit or at that level concern is more potential than reality.
    Yup 35% by weight.
  • @PhilGeis thanks
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