Genetic Diversity of Listeria Detected in the Production Environment of Meat Processing
Bibliographic record
Abstract
Abstract The safety of food production as concerns Listeria is the key to the sanitary wellbeing of manufactured products. Molecular-genetic methods for the analysis of Listeria, including whole-genome sequencing, are effective in monitoring persistent contaminants and in the epidemic investigation of cases of foodborne infections. They have been adopted in the European Union, United States, and Canada. In Russia, multilocus and whole-genome sequencing has proven itself in the analysis of clinical food isolates and Listeria from the environment. The objective of the study was molecular-genetic characterization of Listeria detected in the industrial environment of meat processing. To characterize the Listeria isolates, microbiological methods were used according to GOST (State Standard) 32031–2012, as well as multilocus sequencing, including the analysis of seven housekeeping genes and four virulence genes, as well as whole-genome sequencing. In swabs that were positive for the presence of Listeria spp. taken at two meat-processing plants in Moscow, Listeria monocytogenes constituted 81% and L. welshimeri 19%. The predominant genotype (Sequence Type, ST) of L. monocytogenes was ST8. The variety was supplemented with ST321, ST121, and ST2330 (CC9 (Clonal Complex 9)). L. welshimeri, which prevailed in the second production, was represented by ST1050 and ST2331. The genomic characteristics of L. welshimeri isolates confirmed that they have high adaptive capabilities both as concerns production conditions (including resistance to disinfectants) and the metabolic peculiarities of the gastrointestinal tract of animals. L. monocytogenes CC9 and CC121 are also correlated with food production in other countries. However, L. monocytogenes CC8 and CC321 can cause invasive listeriosis. The concordance in the internalin profile of the ST8 isolates from the industrial environment with the clinical isolates ST8 and ST2096 (CC8) is a cause for concern. The study showed the effectiveness of molecular-genetic methods in determining the diversity of Listeria detected in the production environment of meat processing, and laid the foundation for monitoring of persistent contaminants.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".