Meat defects — ‘‘White spot’’ on stored meat: Which organism is classically implicated in producing visible white spots or patches on meat surfaces?

Introduction / Context:
Surface mycological defects on meat are frequently described by color and texture. ‘‘White spot’’ is a known storage issue, especially under humid, chilled conditions with limited airflow.

Given Data / Assumptions:

• Defect: discrete white patches/spotting on meat surfaces.
• Conditions: refrigerated storage with high humidity.
• Potential fungi include Sporotrichum and various Penicillium species.

Concept / Approach:
Sporotrichum carnis is historically cited for producing white, felt-like growth on meats (‘‘white spot’’). In contrast, Penicillium expansum is better known as a blue mold of fruits; P. oxalicum also does not typify the white spot meat phenotype.

Step-by-Step Solution:
Match phenotype: white, cottony patches on meat. Recall classic association: Sporotrichum carnis. Exclude fruit-associated Penicillia as primary cause in meat.

Verification / Alternative check:
Meat hygiene guides consistently list S. carnis for white surface growth during extended refrigerated storage.

Why Other Options Are Wrong:

• P. expansum: typically blue rot of apples and produce, not classic meat white spot.
• Both (a) and (b): overinclusive; primary culprit is S. carnis.
• P. oxalicum: not the hallmark pathogen for white spot on meat.

Common Pitfalls:
Assuming any white surface equals harmless ‘‘aging’’ mold; some growth indicates handling and humidity control issues.

Final Answer:
Sporotrichum carnis