Moist heat sterilization

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See also: Sterilization (microbiology)

Heating an article is one of the earliest forms of sterilization practiced. Moist heat, as the name indicates, utilizes hot air that is heavily laden with water vapour and where this moisture plays the most important role in the process of sterilization.^[1][2]

Contents 1 Methods used 2 Action on microorganisms 3 See also 4 References

[edit] Methods used

^[3][4]

1. Below 100°C:
   1. Water bath - 56°C for 60 minutes
   2. Vaccine bath - 60°C for 60 minutes
   3. Pasteurization of milk
      1. Holder method - peaks at 63°C for 30 minutes
      2. Flash method - peaks at 72°C for 20 seconds
      3. Ultra high temperature (UHT) method - peaks at 125°C for a few seconds
   4. Fractional sterilization - serum inspissator

1. At 100°C:
   1. Boiling for 10 to 30 minutes
   2. Tyndallizer - steaming for 3 successive days at 100°C to kill all organism in their vegetative forms by allowing the spores time to hatch in between the heating periods.
   3. Steam sterilizer - Steam at atmospheric pressure for 90 minutes

1. Above 100°C:
   1. Autoclave or Pressure cooking

[edit] Action on microorganisms

Moist heat coagulates the proteins in any organism and this is aided by the water vapour that has a very high penetrating property, leading to their death. It also causes oxidative free radical damage. This can even, at high enough temperatures (vide:Autoclave), kill prions.

[edit] See also

Sterility assurance level

[edit] References