Identification of microorganisms isolated from kefir grains in milk and water of different localities
Bibliographic record
Abstract
The kefir is a fermented milk beverage that had its origin in the mountains of Caucasus, in Tibet or in Mongolia, many centuries ago. Another substrate that is used for production of that drink is water and raw sugar in the concentration from 3 to 10%. Kefir grains resemble small cauliflower florets that vary in size from 3 to 30 mm in diameter, are lobed, irregularly shaped, white to yellow-white in colour and have a slimy but firm texture. The structure, the microbiological constitution and the composition of the products formed during the fermentation of the water Kefir grains are similar to the grains cultivated in milk. The objective of this work was to identify the microorganisms present in the grains of milk kefir and water from different Brazilian states, Canada and United States by traditional and molecular methods. The bacterial population varied between 4.95 log10 UFC/g to 10.43 log10 UFC/g in the samples from Minas Gerais and USA respectively, and for yeast, varied from 5.15 log10 UFC/g in the sample from Distrito Federal to 8.77 log10 UFC/g in the sample from São Paulo, when cultivated in milk. However, for samples cultivated in water, values varied between 6.04 log10 UFC/g in the sample coming of Alagoas to 9.18 log10 UFC/g in the sample from Bahia for bacteria, and for yeasts it varied from 5.92 log10 UFC/g in the Minas Gerais sample to 8.30 log10 UFC/g in that from Rio de Janeiro. The microorganisms present in the kefir grains cultivated in milk or in water are similar, being the species belonging to the Saccharomyces, Pichia, Dekkera, Candida, Kluyveromyces, Yarrowia, Zygosaccharomyces, Galactomyces and Saccharomycetes genera, being common the species S. cerevisiae, Pichia fermentans, P. membranifaciens and Yarrowia lipolytica. In the samples the bacteria identified were of the genera Lactobacillus, Bacillus, Gluconacetobacter and Acetobacter. The especies Lac. kefiri, Lac. paracase and Lac. satsumensis species were found in both grains. As to the bacterial species Gluconacetobacter liquefaciens, Acetobacter lovaniensis, A. syzygii, Bacillus cereus, Lac. satsumensis and the yeasts Candida parapsilosis, C. valdiviana, Pichia guillermondii, P. cecembensis, P. caribbica, Zygosaccharomyces mellis and Z. fermentati this study is the first to report their presence in kefir. These results show a great diversity in the microbial population of kefir grains from different sources.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".