Meat discoloration — Yellow patches on meat most often result from bacteria producing yellow pigments, typically belonging to which genera?

Introduction / Context:
Visual defects such as yellowing reduce consumer acceptance of fresh meat. Identifying the likely microbial causes supports targeted sanitation and shelf-life strategies in meat processing and retail display.

Given Data / Assumptions:

• Yellow discoloration is typically due to pigmented bacteria on the surface.
• Common yellow-pigmented genera in meat environments include Micrococcus and Flavobacterium (now split into multiple genera).
• Blue-green or other hues may be associated with different species.

Concept / Approach:
Because both Micrococcus (yellow to orange colonies) and Flavobacterium-like organisms (yellow, often shiny colonies) are classically linked to yellowing, questions of this type expect the inclusive answer that acknowledges both contributors.

Step-by-Step Solution:

Verification / Alternative check:
Meat microbiology references and plant troubleshooting guides list these genera in yellow discoloration cases, especially under chill storage with intermittent temperature abuse.

Why Other Options Are Wrong:

• Micrococcus or Flavobacterium alone: incomplete.
• Pseudomonas syncyanea: associated with different discolorations (bluish-green) and is not the typical source of yellowing.

Common Pitfalls:
Conflating any Pseudomonas growth with yellow patches; pigment profile matters.

Final Answer:
both (a) and (b)