Which of the following pairs correctly matches a method with its principle for controlling microbes?

RRB Nsg. Superintendent-2026 (Shift -2nd)

Applied Microbiology & Infection control

Easy

Appeared in: RRB Nsg. Superintendent-2026 (Shift -2nd)

Explanation

Filtration is a physical sterilization method that works by separating microbes from a fluid (liquid or gas).
It uses a filter with microscopic pores that are too small for microorganisms to pass through, effectively trapping them.
This process removes microbes without killing them, which is why it is the method of choice for sterilizing heat-sensitive materials like vaccines, certain IV solutions, and protein-based drugs.

Option A: Pasteurization uses mild moist heat (e.g., 63-72°C) to reduce the number of pathogenic and spoilage microorganisms, not high pressure.
Option B: Autoclaving is a primary method of moist heat sterilization. It uses steam under high pressure (typically 121°C at 15 psi) to kill all forms of microbial life, including spores.
Option C: Incineration is a method of dry heat sterilization that involves complete combustion (burning) of waste materials at very high temperatures, reducing them to ash.

Visual 1: Diagram: Membrane Filtration. A visual showing a liquid containing microbes being passed through a filter, with the microbes being trapped on the surface while the sterile filtrate passes through.
Visual 2: Infographic: Comparison of Heat Sterilization. A chart comparing Dry Heat (Incinerator, Hot Air Oven) and Moist Heat (Autoclave, Pasteurization) with their respective temperatures, times, and mechanisms.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Principles of Microbial Control Methods as background academic context rather than a clinical decision trigger.
Nurses must understand the principles of different sterilization methods to ensure medical equipment and solutions are safe for patient use, preventing healthcare-associated infections (HAIs).
Filtration is essential in clinical practice for preparing heat-sensitive medications (e.g., certain antibiotics, biologics) and for purifying air in sterile environments like operating rooms and isolation units (using HEPA filters).
What if? If a nurse needed to prepare a heat-labile biologic drug for IV administration, using an autoclave (moist heat) would destroy the drug's therapeutic proteins. This makes filtration the only appropriate sterilization method in this context.

How to Approach the Question

This is a factual recall question that tests your knowledge of different microbial control methods.
Analyze each option as a pair: a 'Method' and its described 'Principle'.
Evaluate Option A: 'Pasteurization'. Recall its principle. It uses mild heat, not high pressure. Therefore, this pair is incorrect.
Evaluate Option B: 'Autoclaving'. Recall its principle. It uses moist heat (steam under pressure), not dry heat. This pair is incorrect.
Evaluate Option C: 'Incineration'. Recall its principle. It uses extreme dry heat (burning), not moist heat. This pair is incorrect.
By elimination, Option D must be correct. Confirm that filtration is indeed a process of physical removal, which correctly matches the described principle.

Concept Tested & Keywords

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