Juice microbiology – Which microorganism is commonly detected in both fresh and frozen fruit juices and can survive low-temperature storage?

Introduction / Context:
Fruit juices, whether fresh or frozen, are susceptible primarily to fungal contamination because many moulds sporulate on fruit surfaces and survive cold storage, later affecting flavor and appearance.

Given Data / Assumptions:

• We compare bacterial indicators with a common juice-associated mould.
• Focus is on organisms recoverable from both fresh and frozen juices.

Concept / Approach:
Penicillium species (including P. chrysogenum) produce hardy spores capable of surviving refrigeration and freezing. Upon thawing or slight temperature abuse, they can grow, causing cloudiness, sediment, off-flavors, and surface mycelium.

Step-by-Step Solution:
Assess bacterial options → many vegetative bacteria decline markedly in frozen juice matrices. Evaluate mould option → Penicillium spores persist in fresh and frozen systems. Therefore, P. chrysogenum is the correct choice.

Verification / Alternative check:
Juice spoilage literature consistently lists Penicillium spp., along with other moulds (e.g., Aspergillus), as frequent contaminants of citrus and apple juices, even after cold storage.

Why Other Options Are Wrong:
E. coli and Enterobacter aerogenes are hygiene indicators but are not typically persistent in frozen juices; C. botulinum does not grow in acidic juices and is not routinely present.

Common Pitfalls:
Relying solely on bacterial indicators for quality in acidic, cold-stored juices; overlooking fungal spores.

Final Answer:
Penicillium chrysogenum.