In vitro growth control of selected pathogens by Lactobacillus acidophilus- and Lactobacillus casei-fermented milk
Bibliographic record
Abstract
AIMS: Food-borne pathogen inhibition was tested in the presence of a mixture of Lactobacillus acidophilus and Lactobacillus casei during fermentation under controlled pH conditions. METHODS AND RESULTS: The growth of Escherichia coli O157:H7, Salmonella serotype Typhimurium, Staphylococcus aureus, Listeria innocua, Enterococcus faecium and Enterococcus faecalis was evaluated for 48 h at 37 degrees C. In the presence of the lactic acid bacteria (LAB), an increase of the generation time was observed for all the gram-positive bacteria evaluated. Staphylococcus aureus was the most sensitive strain showing an increase of the generation time by 210%. However, for all the gram-negative bacteria evaluated, no inhibition occurred after 8 h of fermentation. The soluble portion of Lact. acidophilus- and Lact. casei-fermented milk was recuperated and tested for its antimicrobial activity. Listeria innocua and Staph. aureus were the most sensitive to the presence of fermented milk supernatant showing an inhibition of 85.9% and 84.7%, respectively. This soluble fraction was neutralized to eliminate the antimicrobial effect of the organic acids produced; the most sensitive strains were L. innocua and E. coli O157:H7 showing an inhibition of 65.9% and 61.9%, respectively. Finally, the soluble fraction was neutralized and irradiated at 45 kGy using a (60)Co source to eliminate the possible antimicrobial effect of both organic acids and bacteriocin-like substances. Enterococcus faecalis, E. coli O157:H7 and Staph. aureus were the most affected bacteria by this fraction, showing 39.1, 32 and 31.2% inhibition, respectively. CONCLUSIONS: The results obtained in this study suggest the implication of both organic acids and bacteriocin-like inhibitory substances in the antimicrobial activity observed in the soluble fraction of the probiotic preparation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study revealed the antimicrobial mechanisms of action of Lact. acidophilus- and Lact. casei-fermented milk used to prevent antibiotic-associated diarrhoea.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".