Beer spoilage – Sarcina sickness: The “Sarcina sickness” of beer caused by <em>Pediococcus cerevisiae</em> is characteristically associated with which changes?

Introduction / Context:
Pediococcus species are notorious lactic acid bacteria in breweries. The historical term “Sarcina sickness” reflects the tetrad packing of these cocci and the constellation of faults they cause in beer when hygiene or hop resistance barriers fail.

Given Data / Assumptions:

• Causative agent: Pediococcus cerevisiae (now often Pediococcus damnosus group).
• Beer matrix: low pH, ethanol, iso-alpha acids; yet some strains are hop-resistant.
• Observed faults span acidity, turbidity/ropiness, and carbonation disturbances.

Concept / Approach:
Pediococcus produces lactic acid (sourness), exopolysaccharides (ropey viscosity/haze), diacetyl (buttery), and can trigger gushing (“popiness”) via nucleation changes and CO2 release dynamics. Thus, multiple sensory and physical defects co-occur, making “All of these” the correct, inclusive choice.

Step-by-Step Solution:
Link Pediococcus metabolism to lactic acid production → sourness. Associate exopolysaccharide synthesis → turbidity/ropiness. Recognize carbonation instability and gushing events → popiness. Choose “All of these.”

Verification / Alternative check:
Brewery microbiology texts and QC case studies document these combined symptoms in Pediococcus infections, often alongside elevated diacetyl measurements.

Why Other Options Are Wrong:
Picking any single symptom underestimates the typical multi-fault presentation of Sarcina sickness.

Common Pitfalls:
Attributing haze solely to protein–polyphenol chill haze; persistent ropey viscosity is a spoiler hallmark, not just colloidal haze.

Final Answer:
All of these.