Question

The titrable acidity of cow milk varies from -

• A. 0.13 to 0.14 Percent LA
• B. 0.08 to 0.1 Percent LA
• C. 0.17 to 0.18 Percent LA
• D. 0.18 to 0.19 Percent LA

Hint:

For exams, remember the acidity ranges: Cow milk \(\approx\) 0.13-0.15% LA, and Buffalo milk \(\approx\) 0.16-0.18% LA. Buffalo milk has higher acidity due to its higher content of proteins and phosphates (solids).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Titratable Acidity (TA) measures the total acidity of a milk sample. Freshly drawn milk exhibits a certain level of natural acidity due to its constituents like casein proteins, phosphates, citrates, and dissolved CO\(_2\). This is different from developed acidity, which is caused by the fermentation of lactose into lactic acid by bacteria. The question asks for the normal range of this natural acidity in fresh cow milk, expressed as percent Lactic Acid (% LA).
Step 2: Detailed Explanation:
The natural acidity of fresh, good-quality cow milk is quite consistent.
The accepted standard range for the titratable acidity of fresh cow milk is 0.13% to 0.15% Lactic Acid.
Let's evaluate the given options:
(A) 0.13 to 0.14 Percent LA: This range falls perfectly within the accepted standard for fresh cow milk.
(B) 0.08 to 0.1 Percent LA: This is too low and may indicate adulteration with water or neutralization.
(C) 0.17 to 0.18 Percent LA: This range is slightly high for fresh cow milk and might indicate the beginning of bacterial action or a condition like mastitis. This range is more typical for buffalo milk, which has higher solids.
(D) 0.18 to 0.19 Percent LA: This is definitely high and suggests that the milk has started to sour (developed acidity).
Step 3: Final Answer:
The normal range for titratable acidity in fresh cow milk is 0.13 to 0.14 Percent LA.