Meat spoilage under aerobic storage – Which moulds are responsible for the characteristic green patches that appear on the surface of meats?

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:

  • Storage is aerobic (exposed to air or permeable wrap).
  • The defect is surface green patches without deep tissue invasion.
  • Candidate organisms are Penicillium species typically recovered from chiller rooms and cutting areas.


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.

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion