Q.46 Given below are two statements. one is labelled as Asseltion (A) and the other is labelled as Reason (R) :
Assertion (A) : Salt is added as a preservative for storage of meat.
Reason (R) Salt creates hypettonic environment and most bacteria cannot grow in hypettonic media.
In the light of the above statements. choose the most appropriate answer from the options given below.
1. Both (A) and (R) are correct and (R) is the correct explanation of (A)
2. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
3, (A) is correct but (R) is not correct
4. (A) is not correct but (R) is correct
Salt is indeed added as a preservative for meat storage, and it works by creating a hypertonic environment that inhibits bacterial growth through osmosis. The correct answer is option 1: Both (A) and (R) are correct and (R) is the correct explanation of (A).
Detailed Solution
During meat preservation, salt (NaCl) is applied via dry curing or brining. It dissolves in surface moisture, forming a high-salt concentration that draws water out of meat cells via osmosis, dehydrating the tissue and reducing available water (low water activity, Aw). This hypertonic condition causes plasmolysis in bacteria, preventing their growth and toxin production (e.g., by Salmonella, E. coli, Clostridium).
Option Breakdown
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Option 1: Both correct, R explains A → Correct. Salt’s hypertonic effect directly preserves meat by halting bacterial proliferation.
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Option 2: Both correct, R not explanation → Incorrect. R precisely explains the mechanism behind A.
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Option 3: A correct, R incorrect → Incorrect. R is true; bacteria like most Gram-negatives cannot survive hypertonic stress.
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Option 4: A incorrect, R correct → Incorrect. A is factually true as salt is a standard meat preservative.
Salt Meat Preservation Basics
Salt meat preservation creates hypertonic environment inhibiting bacteria, extending shelf life via osmosis without refrigeration. This Assertion Reason tests microbiology of food preservation for competitive exams.
Mechanism Explained
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Salt draws water from meat cells, lowering Aw below 0.75 (bacteria need >0.91).
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Hypertonic media causes bacterial dehydration, halting metabolism and replication.
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Applies to dry salting (20% salt) or brining; effective against pathogens like C. botulinum.
Assertion Reason Table
| Statement | Status | Explanation |
|---|---|---|
| A: Salt added as meat preservative | Correct | Historical and modern method via dehydration. |
| R: Salt creates hypertonic environment; bacteria can’t grow | Correct | Osmotic stress kills microbes. |
Why Option 1 Wins
R directly explains A: Hypertonic inhibition is salt’s primary antibacterial mode in meat curing, beyond flavor or texture roles. Key for food microbiology in exams.
