Question

Match List-I with List-II

List-I (Causative Organism)	List-II (Defect)
(A) Pseudomonas nigrifaciens	(I) bacterial thickening
(B) Lactococcus lactis spp Lactis biovorin maltigenes	(II) bitterness in evaporated milk
(C) Bacillus panis	(III) black discolouration on butter
(D) Staphylococcus albus	(IV) malty taint

Choose the correct answer from the options given below

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

Hint:

"Nigrifaciens" means "making black." "Maltigenes" means "generating malt flavor." Use the Latin roots in the names of bacteria to identify the spoilage defect!

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Dairy spoilage organisms are often identified by the specific biochemical changes they induce, such as pigment production, enzyme activity, or flavor taints.

Step 2: Detailed Explanation:
1.Pseudomonas nigrifaciens: As the name implies ("nigri" = black, "faciens" = making), this psychrotrophic bacterium produces a black pigment on the surface of salted butter. Thus, (A) matches with (III).
2.Lactococcus lactis spp Lactis biovar maltigenes: This variant of the common starter culture produces 3-methylbutanal, which imparts a distinct "malty taint" to milk and butter. Thus, (B) matches with (IV).
3.Bacillus panis: This is a spore-forming bacterium often associated with "bacterial thickening" or "sweet curdling" in evaporated milk or heat-treated milk due to the production of rennet-like enzymes. Thus, (C) matches with (I).
4.Staphylococcus albus: This organism is sometimes implicated in the development of "bitterness" in evaporated milk due to its proteolytic activity. Thus, (D) matches with (II).
Based on this, the correct sequence is A-III, B-IV, C-I, D-II.

Step 3: Final Answer:
The correct matching is (A)-(III), (B)-(IV), (C)-(I), (D)-(II).