Difficulty: Easy
Correct Answer: All of these
Explanation:
Introduction / Context:
Green surface discolorations on aerobically stored meats are a classic quality defect in meat microbiology. Recognizing the principal moulds that generate these green patches helps processors design prevention strategies (temperature control, air handling, sanitation).
Given Data / Assumptions:
Concept / Approach:
Penicillium spp. are psychrotolerant moulds common in cold rooms. They sporulate readily on meat surfaces where condensation and oxygen are present, producing pigmented colonies (often blue-green to green). Multiple species, not just a single one, are implicated.
Step-by-Step Solution:
Identify storage ecology → chilled, humid, oxygen-rich conditions favor Penicillium.
Match visual cue → green colonies are consistent with Penicillium growth on proteinaceous surfaces.
Cross-check species reports → P. expansum, P. asperulum, and P. oxalicum have all been reported on chilled meats.
Therefore, the most comprehensive correct option is “All of these”.
Verification / Alternative check:
Environmental swabbing in deboning rooms commonly detects mixed Penicillium flora on walls, evaporator fins, and air ducts; controlling humidity, air flow, and sanitation reduces green spot incidence.
Why Other Options Are Wrong:
Any single species option is incomplete; multiple Penicillium species cause this defect. Cladosporium can grow in chillers but is more often linked with dark, olive-black spots rather than the characteristic Penicillium green patches.
Common Pitfalls:
Confusing green mould growth with chemical oxidation of myoglobin; mould discoloration usually includes fuzzy colony morphology and sporulation.
Final Answer:
All of these.
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