Question

______ lacks Leuconostoc as the flavour producer.

• A. B and L culture
• B. D and O culture
• C. BD and DL culture
• D. B and O culture

Hint:

To remember starter culture classifications: 'D' stands for Diacetylactis, 'L' or 'B' stands for Leuconostoc (Betacoccus), and 'O' stands for Zero (no aroma producer). If a culture is labeled 'D and O', it contains no 'L' or 'B' component and thus lacks Leuconostoc.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Starter cultures in the dairy industry are specialized mixtures of lactic acid bacteria used to initiate milk fermentation.
These cultures are categorized based on their fermentation temperature requirements and their ability to produce flavor and aroma compounds.
The primary compound responsible for the characteristic buttery aroma in fermented dairy products is diacetyl.
The main flavor-producing bacteria added to starter cultures to synthesize diacetyl are Leuconostoc species and certain citrate-utilizing lactococci.
If a culture lacks these specific organisms, it cannot produce the desired aromatic profile.

Step 2: Detailed Explanation:
Mesophilic starter cultures are historically classified into five distinct groups based on their aroma-producing microflora: O, D, L, BD, and DL.
The 'O' culture (often called 'N' culture) consists entirely of homofermentative acid producers such as Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris.
This culture is used purely for acid development and completely lacks any aroma-producing microorganisms.
The 'D' culture contains acid producers alongside Lactococcus lactis subsp. lactis biovar. diacetylactis, which serves as the sole flavor producer.
The 'L' culture (historically designated as 'B' for Betacoccus) utilizes Leuconostoc mesenteroides subsp. cremoris or Leuconostoc lactis to produce diacetyl.
The 'BD' or 'DL' cultures combine both L. diacetylactis and Leuconostoc species to achieve rapid acid production and a robust, balanced flavor profile.
Since 'D' cultures use L. diacetylactis and 'O' cultures contain no flavor producers, the combination of D and O cultures contains absolutely no Leuconostoc species.
Thus, the D and O culture is the correct choice as it lacks Leuconostoc as the flavor producer.

Step 3: Final Answer
The D and O culture combination lacks Leuconostoc as the flavor producer.