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    • #15974
      pi87
      Participant

      Hi.

      I’m wondering whether bacteria and fungi can be present or can grow in drysol: an antiperspirant consisting of absolute ethanol and aluminum chloride hexahydrate. We got some results from a rather unserious foreign lab:

      Bacteria testing: sampling made 1:10 test liquid. In 80 Twain agar, 38°C,foster 48 hours.
      Results: < 1000 (cfu/g)

      Yeast & mold test: sampling made 1: 10 test liquid. In Tiger red AGAR, 28 °C foster 72 hours.
      Results: < 100 (cfu/g)

      Can these results be right? Can anything survive in these environments?

      Thanks!

    • #109153
      JackBean
      Participant

      well, 0 < 1000 😉

    • #109162
      canalon
      Participant

      And to add to Jackbean’s answer since they did not plate a full gram of sample, they have to limit their results to the lower limit they could detect reliably, hence the <1000 rather than 0

    • #109167
      pi87
      Participant

      If "no pathogens" are present, must this number be 0?
      Thanks

    • #109168
      JackBean
      Participant

      it will hardly be <0 and if it is >0, then there is some growth 😉
      However, it’s always kind of probability numbers, especially for low counts. That’s probably also reason, why they do not clearly state 0 cfu/g, but rather give some limit.

    • #109176
      canalon
      Participant

      No you can never be sure that it is absolutely 0, so you just say that it is below your detection limit. Which is good enough.

    • #109179
      michimichi
      Participant

      we dont report 0 as a result, The value <100 or <1000 means the sample was diluted.
      it is synonymous to 0. or you can say "absent or negative" if you are only pertaining to quality.

    • #109181
      JorgeLobo
      Participant

      It’s hard to know what pi87 is asking as the report offers no confdence anything was detected. Agree th 1:10 dilution cited doesn;t seem consistent with the <1000 report. My bet is the diluton factor is stated incorrectly as substantial dilution is necessary to neutralize product carryover. Although one can recover spore forming bacteria and even vegetative bacteria (in biofilm) from ethanol, antiperspirant aluminum Cl salt renders the product very acidic so it’s pretty hostile and would require a fair amount of dilution to neutralize.

    • #109182
      michimichi
      Participant

      mostly no microorganism can survive in that environment specially those susceptible or"weak microorganisms".but yes, a spored microorganisms can may survive . cosmetics can be contaminated (mostly yeast and molds) after production, during filling, packaging, the way they handle the cosmetic.Obviously they grow only on the surface of the cosmetic as an indication of contamination.
      That is why we use the antimicrobial efficacy test/challenge test to determine the efficacy of its preservative.

    • #109183
      JorgeLobo
      Participant

      No – the most common contaminants of cosmetics are bacterial – esp. is Burkholderia cepacia and grow throughout the product. Contamination is most frequently associated with water – poor quality process water or cleaning water such as from failed draining of systems after washoutincubating in equipment inclding those mentioned.

      Mold contamination is a relatively rare event in comparison. It is typically limited to the surface of semiolid cosmetics in open jars and is probably as much a consumer as manufacturing issue – so is pretty obvious when it does occur. Yeast contamaintion is also somewhat rare and is not surface limited.

      The AET is useful but not insurances. Cosmetic micro quality is as much a function of process hygiene as preservation as bacteria can adapt/ develop tolerance and resistance to any preservative given the right opprtunity.

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