is the best method for milk preservation. - DSSSB 13 August 2024

DSSSB 13 August 2024

Applied Microbiology & Infection control

Easy

Appeared in: DSSSB 13 August 2024

Explanation

Pasteurisation is defined as heating milk to a specific temperature for a set duration to destroy pathogens while causing minimal changes to its composition, flavor, and nutritive value.
It is the standard method for making milk safe for consumption by killing common milk-borne pathogens like Mycobacterium tuberculosis, Brucella, and Salmonella.
Common methods include the Holder (vat) method (63°C for 30 minutes) and the High-Temperature Short-Time (HTST) or Flash method (72°C for 15 seconds), followed by rapid cooling.
Unlike sterilization methods that aim to kill all microorganisms, pasteurization targets only pathogenic and spoilage organisms, thus preserving the quality of the milk.

Option A: Inspissation is a method used to solidify and sterilize protein-rich media, such as egg or serum for bacteriological cultures (e.g., Lowenstein-Jensen medium). It is not used for preserving liquid milk.
Option B: Incineration is a terminal sterilization method that involves burning materials to ash at extremely high temperatures. It is a method of waste disposal, not preservation, as it completely destroys the material.
Option D: Tyndallization, also known as fractional sterilization, is used for sterilizing culture media that cannot be heated above 100°C (e.g., those containing sugars or gelatin). It is a multi-day process and is not practical or designed for routine milk preservation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Methods of sterilization and disinfection for food preservation as background academic context rather than a clinical decision trigger.
Understanding pasteurization is fundamental in public health nursing to prevent the spread of milk-borne diseases like tuberculosis, brucellosis, listeriosis, and salmonellosis.
Nurses play a key role in educating communities, especially vulnerable populations like pregnant women, children, and immunocompromised individuals, on the importance of consuming pasteurized dairy products to avoid infection.
What if? If a patient in a remote area only has access to raw (unpasteurized) milk, a nurse should advise them to boil the milk thoroughly before consumption. Boiling serves as an effective home-based method to kill most harmful bacteria, acting as a form of high-temperature heat treatment.

How to Approach the Question

First, identify the core subject of the question, which is the 'best method for milk preservation'.
Next, review the given options, which are all methods of sterilization or disinfection.
Recall the specific application for each method. Ask yourself, 'What is this method typically used for?'
Pasteurisation is a term specifically associated with treating heat-sensitive liquids like milk and juice to make them safe for consumption without destroying them.
Compare this primary use to the others: Inspissation (solidifying culture media), Incineration (waste destruction), and Tyndallization (sterilizing sensitive media). This contrast confirms Pasteurisation is the only suitable choice for preserving milk.

Concept Tested & Keywords

Concept Tested: Methods of sterilization and disinfection for food preservation.
Stem keywords: milk preservation, best method
Lead-in keywords: best

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 191-193