Surfactant turning pink problem

Hi, I really need your guys advise. I'm making common body wash without colorant. At first it turns out good (transparant white, and pearly white when added with glycol distearate). However 3-4 days later, it turned so pink that it the color changed is easily noticeable. 

I had asked my lecturer and she only gave me 2 reason:
- Sodium Hydroxymethylglycinate can turned emulsion/surfactant pink --> I did not use this at all.
- Too acidic may turned emulsion/surfactant pink. --> I supposed my pH should be fine. I did not adjust because the final pH goes around 6.

I really had no clue at all. Is this mould? I used RO water which mean the water is clean and should not be a problem. Its quite hot here in Indonesia, but I put it in nice indoor without direct sunlight.

My formula is: 

To 100 Water 
0.2 Glycerin
0.2 Disodium EDTA 
14.2 Sodium Lauryl Ether Sulfate (70%) = 10% active
10 Cocamidopropyl Betaine (30%) = 3% active
2.0 Decyl glucoside
2.0 Lauryl Glucoside
1.0 PEG-40 Hydrogenated Castor Oil
0.6 PEG-7 Glyceryl Cocoate
0.6 Glycol Distearate 
0.6 Dipropylene glycol 
2.0 Fragrance oil
0.6 DMDM Hydantoin
0.3 Potassium Sorbate

Thank you and would really appreciate if someone can help me with this issue.


  • PerryPerry Administrator, Professional Chemist
    It could be some compound in your fragrance oil. I'd try to make a batch without fragrance and see if you still have the problem.  Also, it could be a microbial contamination problem.  Do a microbial test to see if the pink solution is contaminated.
  • BelassiBelassi Member, PCF student
    I can't see anything here suspicious except as Perry said, the fragrance. Which seems high at 2%. The preservative system looks very adequate so I doubt it will be 'off', but have it checked anyway.
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • Thank you Perry and Belassi for your advise and the time to read my post. I'm also suspecting the Fragrance oil. Until today I have no idea that FO can possibly turns the surfactant color into pink. The one that turns really pink is somewhat like citrusy, orange and lemon FO.

    The other which I use somekind like marine/ocean FO also turns from white to ivory color (hints that it turned into slight yellowish). 

    Its really hard to do microbial testing in my small workshop right now. I'm trying to be as sterile as possible. Including the bottle from suppliers, I washed it with 200ppm Chlorine and air dry it before packaging.

    Do you think I need to sterilize with Ethanol or IPA again before packaging?
    As for the 2% FO, I will try to reduce into 1.5%. I was taught to limit up to 0.6% only, but the problem is everytime i do market research, all of potential customers says its aroma is not strong enough. All my competitors has strong smell and lingers on skin quite long time.

    Thank you very very much for your insight. :)
  • PerryPerry Administrator, Professional Chemist
    Ultimately, you could do a Knockout Experiment to isolate the cause.
  • Thank you for your guidance :)
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