Nutrition: phosphatase test: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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PSM · Nutrition: phosphatase test

Sample item

A milk sample is tested for efficiency of pasteurisation. A negative alkaline phosphatase test indicates that the milk has been:

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Properly pasteurised

Alkaline phosphatase is destroyed at temperatures slightly above those needed to kill pathogens, so absence of the enzyme shows adequate pasteurisation. A positive test indicates under-heating or addition of raw milk.

Option by option

  • A. Properly pasteurised (correct)

    Correct. Absence of enzyme shows proper pasteurisation.

  • B. Adulterated with water

    Water addition is detected by lactometer readings.

  • C. Contaminated after pasteurisation

    Post-pasteurisation contamination is detected by coliform tests.

  • D. Inadequately heated

    Inadequate heating would give a positive test.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this PSM question

What is the answer to this PSM question?

The best answer is A, Properly pasteurised. Alkaline phosphatase is destroyed at temperatures slightly above those needed to kill pathogens, so absence of the enzyme shows adequate pasteurisation.

Why is "Adulterated with water" not the answer?

Water addition is detected by lactometer readings.

Why is "Contaminated after pasteurisation" not the answer?

Post-pasteurisation contamination is detected by coliform tests.

Why is "Inadequately heated" not the answer?

Inadequate heating would give a positive test.

What concept does this question test?

It tests Nutrition: phosphatase test in PSM. A positive test indicates under-heating or addition of raw milk.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Nutrition: phosphatase test?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.