Autoclaving and Sterilization Process

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the purpose of a replaceable HEPA filter?

To separate particles of different sizes (correct)

To denature proteins

To inhibit microbial growth

To dehydrate cells

At what temperature does freezing typically stop microbial growth?

5°C

0°C

-10°C (correct)

-5°C

What is the effect of high pressure on proteins?

It denatures them (correct)

It has no effect on them

It destroys them

It activates them

What is the purpose of desiccation in food preservation?

To remove water from food Signup and view all the answers

What is the effect of osmotic pressure on microbial cells?

It causes plasmolysis Signup and view all the answers

What is the purpose of low-temperature storage?

To slow down microbial growth Signup and view all the answers

What type of microorganisms can grow at low temperatures?

Psychrophiles Signup and view all the answers

What is the purpose of lyophilization in food preservation?

To remove water from food Signup and view all the answers

What is the temperature required to destroy vegetative microorganisms, bacterial endospores, and viruses during autoclaving?

121.5oC Signup and view all the answers

What is the primary mechanism by which autoclaving achieves sterilization?

Increased pressure forces steam into materials Signup and view all the answers

What is the purpose of using pressure-sensitive tape or spore strips during autoclaving?

To ensure proper sterilization of materials Signup and view all the answers

What is the minimum time required for autoclaving at 15 psi and 121.5oC to achieve sterilization?

20 minutes Signup and view all the answers

What type of processing is autoclaving an example of?

High Pressure Processing Signup and view all the answers

What is the result of increasing pressure during autoclaving?

An increase in temperature Signup and view all the answers

What is the purpose of soaking filter paper disks in a chemical and placing them on a culture?

To observe the zone of inhibition Signup and view all the answers

What is the mechanism of action of phenol and phenolics?

They disrupt plasma membranes, causing leakage Signup and view all the answers

What is the characteristic of bisphenols?

They contain two phenol groups connected by a bridge Signup and view all the answers

What is the mechanism of action of chlorhexidine?

It disrupts plasma membranes, causing leakage Signup and view all the answers

What is the mechanism of action of iodine?

It impairs protein synthesis and alters membranes Signup and view all the answers

What is the term for a solution of iodine in aqueous alcohol?

Tincture Signup and view all the answers

Study Notes

Autoclaving

Increased pressure raises the temperature above 100°C and forces steam into materials being sterilized
Autoclaving at 15 psi at 121.5°C for 20 minutes destroys vegetative microorganisms, bacterial endospores, and viruses
Pressure-sensitive tape or spore strips can be used as a quality control measure to ensure proper autoclaving

Chemical Methods to Inhibit Microbial Growth

Phenol and phenolics injure lipids of plasma membranes, causing leakage
Bisphenols contain two phenol groups connected by a bridge and disrupt plasma membranes
Examples of bisphenols include hexachlorophene and triclosan
Biguanides, such as chlorhexidine, are used in surgical hand scrubs and disrupt plasma membranes
Halogens, such as iodine, impair protein synthesis and alter membranes

Physical Methods to Inhibit Microbial Growth

Low temperature inhibits microbial growth by slowing down microbial metabolism
Examples of low temperature include refrigeration (5°C) and freezing (-10°C)
High pressure can denature proteins
Cold storage at low temperatures can inhibit growth, but psychrophiles can still grow
Dessication removes water from cells, inhibiting growth and metabolism
Osmotic pressure uses high concentrations of salts and sugars to create a hypertonic environment, causing plasmolysis
Drying methods include desiccation, lyophilization (freeze-drying), and adding salt or sugar to food

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the process of autoclaving, a method of sterilization that uses high pressure and temperature to kill microorganisms. It explains how increased pressure raises the temperature above boiling point, forcing steam into materials to be sterilized.