Wine spoilage ecology — Which groups of microorganisms can cause spoilage faults in wines under unfavorable conditions?

Introduction / Context:
Even after primary fermentation, wines can be spoiled by diverse microbes if hygiene, sulfur dioxide, acidity, or storage conditions are inadequate. Recognizing the range of spoilers helps winemakers implement multi-hurdle controls (SO2, sanitation, filtration, temperature management).

Given Data / Assumptions:

• Wine contains ethanol and organic acids that inhibit many, but not all, microbes.
• Residual sugars, oxygen ingress, and low SO2 create risk windows.
• We include organisms present from grapes, barrels, and bottling lines.

Concept / Approach:
Wild yeasts (e.g., Brettanomyces/Dekkera, film-forming Candida) produce phenolic off-notes, mousy taints, and surface films. Moulds may contribute earthy/musty aromas via metabolites and can introduce enzymes or mycotoxins pre-ferment. Bacteria such as Acetobacter (volatile acidity) and lactic acid bacteria (e.g., Lactobacillus, Pediococcus) cause turbidity, gassiness, diacetyl faults, and malolactic issues. Therefore, all listed groups can cause spoilage depending on conditions.

Step-by-Step Solution:

Verification / Alternative check:
Enology references describe “Brett” spoilage, acetic acid bacteria blooms, and lactic souring as major wine faults, proving contributions from all three groups.

Why Other Options Are Wrong:

• Single-group answers ignore the multi-microbial nature of wine faults.

Common Pitfalls:
Assuming ethanol alone guarantees stability; oxygen control and SO2 management remain critical.

Final Answer:
all of these