For effective sterilisation in an autoclave, the temperature should be:

DSSSB 12 August 2024

Applied Microbiology & Infection control (E5)

Easy

Appeared in: DSSSB 12 August 2024

Explanation

Autoclaving utilizes pressurized steam (moist heat), which is the most effective agent for sterilization.
The standard and minimum effective temperature required to achieve sterilization in an autoclave is 121°C.
This temperature, when combined with a pressure of 15 pounds per square inch (psi), ensures that the steam can penetrate materials and destroy all forms of microbial life.
The most resilient forms of life, bacterial spores, are reliably killed under these conditions, typically with an exposure time of 15-20 minutes.

Option A: This temperature, 127°F, is equivalent to approximately 53°C. This is a pasteurization temperature, which reduces microbial count but does not achieve sterilization as it cannot kill bacterial spores.
Option B: A temperature of 90°C is insufficient for sterilization. While it can kill many vegetative bacteria (disinfection), it cannot reliably destroy heat-resistant bacterial spores.
Option D: This temperature, 90°F, is equivalent to approximately 32°C. This is near human body temperature and is an ideal temperature for the growth and proliferation of many pathogenic bacteria, not for killing them.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles of moist heat sterilization and autoclave operation as background academic context rather than a clinical decision trigger.
Proper autoclave operation is a fundamental pillar of infection control in all healthcare settings, crucial for preventing healthcare-associated infections (HAIs).
Nurses must verify that surgical instruments and other critical items have been properly sterilized by checking the chemical indicators on the packaging and ensuring the integrity of the pack before use.
A nurse's role includes ensuring that items sent for sterilization are correctly cleaned and packaged, as residual organic matter can inhibit the sterilization process.

How to Approach the Question

Recognize that the question is asking for a standard, factual value related to a core nursing procedure.
Identify the key terms: 'autoclave', 'effective sterilisation', and 'temperature'.
Recall the three critical parameters for autoclaving: Temperature, Pressure, and Time.
Scan the options. Notice that two are in Celsius (°C) and two are in Fahrenheit (°F). The standard parameters are almost always taught in Celsius.
Eliminate the Fahrenheit options as they are either too low (90°F ≈ 32°C, a growth temperature) or incorrect (127°F ≈ 53°C, a pasteurization temperature).
Between the Celsius options, recall that 121°C is the standard minimum temperature for killing all microbial life, including spores, under pressure.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart A (pp 26-201 of 604) pp. 126-128, 127-129