Table olives quality: Gassy spoilage of green olives is usually attributed to which group of bacteria?

Introduction / Context:
In olive fermentation and storage, abnormal gas formation can lead to swollen containers, floating fruit, and texture defects. Understanding the typical microbial culprits behind “gassy spoilage” enables targeted control through salt, acidification, and hygiene management.

Given Data / Assumptions:

• Green olives are brined; early stages can permit opportunistic growth if acidification is delayed.
• We consider gas-forming bacteria capable of fermenting sugars under low-acid conditions.
• Common spoilers in vegetables include Enterobacteriaceae and anaerobic spore-formers.

Concept / Approach:
Enterobacter species (formerly grouped with Aerobacter/Klebsiella-type coliforms) are frequently implicated in gassy spoilage of green olives, especially when brine strength or acidification is inadequate. While Clostridium can produce gas in some vegetable ferments, olives’ salt and emerging acidity usually limit strict anaerobes relative to facultative Enterobacteriaceae during early spoilage. Bacillus is not typically the primary gas former in this product context.

Step-by-Step Solution:
Identify early brine conditions that favour coliform growth (moderate salt, insufficient acid). Link gas formation and turbidity to Enterobacter activity. Choose Enterobacter species as the usual cause.

Verification / Alternative check:
Olive fermentation literature highlights coliform contamination as a leading cause of “gassy” defects; corrective actions focus on brine strength, rapid acidification, and sanitation.

Why Other Options Are Wrong:

• Clostridium: Possible in low-acid, anaerobic vegetables but less typical in properly salted olive brines.
• Bacillus: Aerobic spore-formers are less associated with gassy olive spoilage.
• All of these / Pseudomonas only: Overbroad or incorrect for this specific defect.

Common Pitfalls:
Assuming all gas defects are clostridial; in many brined vegetables, early coliforms are the main concern.

Final Answer:
Enterobacter species are usually responsible for gassy spoilage of green olives.