Question

Match each microorganism with the correct activity:

Name of micro-organism	Activity associated
(A) Pseudomonas	(I) Pathogenic and spoilage both
(B) S. thermophilus; L. lactis ssp. lactis	(II) Flavour production
(C) Enterobacteriaceae	(III) Spoilage
(D) L. lactis subsp. lactis bv. diacetylactis	(IV) Acid Production

Choose the correct answer from the options given below:

• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)
• (A) - (II), (B) - (III), (C) - (IV), (D) - (I)
• (A) - (III), (B) - (II), (C) - (I), (D) - (IV)
• (A) - (IV), (B) - (I), (C) - (II), (D) - (III)

Hint:

Associate the sub-species "diacetylactis" directly with diacetyl synthesis, which is the primary source of buttery Flavour production (D--II). This easily distinguishes it from standard acid producers.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Microorganisms in dairy science are classified according to their biochemical and physiological activities, acting either as starter cultures, spoilage agents, or pathogenic hazards.

Step 2: Detailed Explanation:
Let us match the microorganisms in List-I with their associated activities in List-II:
1. (A). Pseudomonas: This genus consists of psychrotrophic bacteria that release heat-stable lipases and proteases, serving as a primary cause of cold-stored milk Spoilage. Hence, (A) matches with (III).
2. (B). S. thermophilus; L. lactis ssp. lactis: These are homofermentative starter cultures used to ferment lactose into lactic acid, primarily responsible for Acid Production in dairy fermentation. Hence, (B) matches with (IV).
3. (C). Enterobacteriaceae: This family contains both environmental spoilage organisms (like coliforms) and key foodborne pathogens (like Salmonella and E. coli), making them responsible for Pathogenic and spoilage both activities. Hence, (C) matches with (I).
4. (D). L. lactis subsp. lactis bv. diacetylactis: This specialized aroma-producing starter culture ferments citric acid to produce diacetyl, which is responsible for Flavour production in butter and fermented milks. Hence, (D) matches with (II).
This yields the combination: (A) - (III), (B) - (IV), (C) - (I), (D) - (II).

Step 3: Final Answer
The correct matching sequence is given by option (A).