Page 29 - MNU-PM502- Pharmaeutical Microbiology Theoritical Book

Pharm D- Clinical Pharmacy Program Third Level Pharmaceutical Microbiology& Antimicrobials (PM 502)

• Pasteurization extends the shelf life of a product and reduces the level of pathogens
in the product.

• UHT milk, if not opened, has a typical unrefrigerated shelf life of six
to nine months.

• Pasteurization is not a method of sterilization.

• Vaccines of non-sporing bacteria are also sterilized by heating
at 60°C for 1 hour in special water baths

• Serum and body fluids with coagulable proteins are also
sterilized at 56°C for 1 hour in water baths.

2- At temperature 100˚C

Boiling at 100°C is a moist heat technique that isn’t recommended for complete
sterility but used for disinfection.

• Holding period 10-30 min.
• The lid of the boiler must not be opened during the
period
• The killing activity can be enhanced by addition of 2%
sodium bicarbonate.

• Used for disinfecting Baby’s Feeding Bottle,
drinking water relatively safer for human
consumption

• Boiling at 100°C kills the vegetative cells is a sure means of disinfection (not
sterility)

Tyndallization (intermittent sterilization)

- A process from the nineteenth century for sterilizing substances
- consists of heating the substance to boiling point (or just a little below boiling
point) for 15-30 minutes, three successive days.

• A method of sterilization that kills both microorganisms and their endospores.

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