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Biological Indicator for Moist Heat (Steam) Sterilization Processes


Learn about the Biological Indicators as Geobacillus stearothermophilus (Bacillus stearothermophilus) used to validate Steam Sterilization in Pharmaceuticals.
Spores of suitable strains of Geobacillus stearothermophilus (Bacillus stearothermophilus) (ATCC 7953 & 12980; NCTC 10003; NCIMB 8157; CIP52.81) are used for validating and assessing routine performance of sterilizers and sterilizing processes employing moist heat as the sterilising agent at temperatures of 121°.For routine monitoring, the D121 value shall be not less than 1.5 minutes.
For processes where the temperature employed is less than 121° (Sterilization of heat- sensitive liquids or containers etc.,) microorganisms such as Bacillus subtilis "5230" may be used.

Related: Low Temperature Sterilization Process (115°C)

Identification

The biological indicator organism complies substantially with the morphological, cultural and biochemical characteristics of the strain of Geobacillus stearothermophilus that is stated in the labelling: under microscopic examination it consists of Gram-positive rods with oval endospores in subterminally swollen cells. When incubated in nutrient broth for 17 hours and used to inoculate appropriate solid media, growth occurs when the inoculated media are incubated aerobically for 24 hours at 55° to 60°, and similar inoculated media incubated concomitantly at 30° to 35° show no evidence of growth in the same period.

Biological Indicators

Any of the following may be used.

Biological Indicator for Steam Sterilization, Paper Carrier

It is a defined preparation of viable spores made from a culture derived from a specified strain of Geobacillus stearothermophilus on a suitable grade of paper carrier, individually packed in a suitable container readily penetrable by steam and characterised for predictable resistance to steam sterilization. It has a particular labelled spore count per carrier of not less than 104 and not more than 108 spores.

Biological Indicator for Steam Sterilization, Self Contained

It consists of a Biological Indicator for Steam Sterilization, Paper Carrier individually packaged in a suitable container readily penetrable by steam and designed to hold an appropriate bacteriological culture medium in a separate ampoule. After subjection to saturated steam sterilization conditions, the ampoule of growth medium is suitably crushed so as to enable the paper carrier to be immersed and incubated in the growth medium which contains a suitable indicator for determining by a color change whether or not spores have survived.

Biological Indicator for Steam Sterilization, Sealed Ampoule

It is a defined preparation of viable spores made from a culture derived from a specified strain of Geobacillus stearothermophilus which is inoculated into an appropriate bacteriological growth medium, and hermetically sealed in a suitable container. It is sensitive to temperature only and primarily used for steam sterilization of liquids. After subjection to saturated steam Sterilization conditions, the ampoule is incubated at the specified temperature. The growth medium contains a suitable indicator for determining by a color change whether or not spores have survived.

Also see: New Genetically Engineered Biological Indicators

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of Pharmaceutical Guidelines, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
Email: .moc.enilediugamrahp@ofni Need Help: Ask Question


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