Postharvest hygiene – Saprophytic bacteria in piled, wet, self-heating vegetables most commonly cause which defect?

Introduction / Context: When harvested vegetables are piled poorly with excess moisture and inadequate ventilation, self-heating and surface wetness promote saprophytic bacterial growth leading to off-quality defects.

Given Data / Assumptions:

• Vegetables are piled wet and show self-heating (exothermic respiration plus microbial activity).
• Focus is on saprophytic (non-pathogenic) bacterial action.

Concept / Approach: Saprophytes readily colonize wet surfaces, producing exopolysaccharides and acids that create slimy textures and sour odors. This is distinct from specific plant diseases (e.g., black rot) caused by particular pathogens.

Step-by-Step Solution: Wet, oxygen-limited microenvironments in piles → favor saprophytic surface growth. Metabolic by-products → polysaccharide slime layers and organic acids → sliminess and souring. Thus, the hallmark defect is sliminess/souring rather than distinct pathogenic rots.

Verification / Alternative check: QA inspections often record slippery surfaces and sour smell in improperly stored piles, resolving when aeration, drainage, and temperature are corrected.

Why Other Options Are Wrong: Brown/black rots are typically tied to specific pathogens; primary bacterial soft rot involves pectinolytic plant pathogens, not general saprophytes.

Common Pitfalls: Assuming all spoilage is due to plant pathogens; saprophytes can cause major quality losses without classical disease lesions.

Final Answer: Sliminess or souring in piled, wet and heating vegetables.