Dissolved Carbon Dioxide Selects for Lactic Acid Bacteria Able to Grow in and Spoil Packaged Beer
Bibliographic record
Abstract
Lactic acid bacteria (LAB) are frequently found as beer-spoilage organisms (BSOs). Correctly identifying a LAB as a BSO is problematic, given that there are few known genetic markers that distinguish beer-spoiling from non-beer-spoiling LAB. Currently, genes purported to participate in hop-tolerance mechanisms are heavily relied upon to indicate LAB isolates with the potential to spoil beer, even though these genes do not consistently correlate with beer-spoilage. Though the presence of hops certainly is a significant physiological stress for bacteria in beer, we demonstrate here that the presence of CO2 dissolved in beer is a strong selective pressure for true LAB beer-spoilage ability (i.e., the ability to grow in and spoil a finished and packaged beer). We screened 20 LAB for their capability to survive and grow in gassed beer at 22 and at 30°C, and discuss the results in relation to ethanol and hop tolerance. Functional gene comparisons of nine dissolved CO2-tolerant and nontolerant genomesequenced isolates reveal potential metabolic pathways of interest for further study, specifically those that deal with cell dormancy and stress responses. These results further our understanding of LAB BSOs and have implications for how best to analyze these bacteria in laboratory settings and to test for these bacteria in the brewery.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".