Sauerkraut defect – slimy or ropy kraut: Which organismal type is most commonly implicated in producing a slimy, ropy texture in kraut due to exopolysaccharide formation?

Introduction / Context:
Slimy or ropy kraut is an undesirable texture defect in fermented cabbage. It is generally associated with exopolysaccharide (EPS) production by certain lactic acid bacteria. Recognizing the primary causative organisms helps processors adjust fermentation conditions and starter cultures.

Given Data / Assumptions:

• Ropiness arises from polysaccharide capsules or EPS in the brine.
• Several Lactobacillus species can produce EPS under certain conditions.
• Kraut is a lactic fermentation dominated by hetero- and homofermentative LAB.

Concept / Approach:
Encapsulated strains of Lactobacillus plantarum are classically cited as major contributors to ropy texture in kraut, although L. brevis can also be implicated. Temperature, salt level, and sugar availability modulate EPS expression. The most representative single choice is the encapsulated L. plantarum group.

Step-by-Step Solution:
Identify texture defect: viscous, thread-forming brine indicates EPS.Associate EPS with encapsulated LAB, especially L. plantarum.Consider contributing factors: excess sugar, low salt, and suboptimal temperature can favor EPS.Select L. plantarum as the primary agent among listed options.

Verification / Alternative check:
Adjusting NaCl to recommended ranges, using reliable starters, and controlling temperature often prevents ropiness, supporting the microbial causation model centered on LAB EPS producers.

Why Other Options Are Wrong:

• Lactococcus lactis: less associated with kraut ropiness in vegetable fermentations.
• L. brevis: can contribute but is not as consistently implicated as L. plantarum; the question expects the primary example.
• None of the above/yeasts: yeasts impact flavor and gas but are not the main EPS ropiness cause.

Common Pitfalls:
Attributing ropiness to pectin breakdown (that yields softening, not viscosity); ignoring that EPS defects often correlate with process drift.

Final Answer:
Encapsulated varieties of Lactobacillus plantarum.