Efficacy of Essential Oils From Some African Spices Against Two Strains of Bacillus cereus Isolated From Vegetable Salad
Bibliographic record
Abstract
<p>Chemical preservatives have been used to preserve our foods against spoilage and pathogenic microorganisms over the years. Consumers now frown at this hence the need to source for preservatives from natural sources. In this investigation fifteen samples of vegetable salad were collected from retail outlets in Lagos, Nigeria dilutions of which were plated on Brilliance <em>Bacillus cereus </em>agar. Isolates were identified based on morphological, biochemical characteristics and reactions to API 20E and API 50 CHB/E test kit. Two strains of <em>Bacillus cereus</em>; <em>B. cereus </em>1 and <em>B. cereus </em>2 were isolated. The organism was spread evenly on Mueller -Hinton agar and wells of 5mm in diameter were made on the inoculated agar with sterile cork borer. Different dilutions (1, 0.1, 0.01, 0.001 mg/ml) of essential oils extracted from three African spices; <em>Aframomum melegueta, Xylopia aethiopica </em>and<em> Piper guineense</em> by hydro distillation method were introduced into the wells in triplicate. After incubation diameter of zones of inhibition were measured. The essential oils of the spices inhibited growth of the two strains. <em>A. melegueta</em> produced the greatest zone of inhibition (14 to 24 mm) and with the lowest minimum inhibitory concentration (MIC) of 31.25 mg/ml, followed by <em>X. aethiopica </em>(10 to 18 mm) with MIC of 62.5 mg/ml and <em>P. guineense </em>(11 to 15 mm) and MIC of 125 and 250 mg/ml against <em>B. cereus </em>1 and <em>B. cereus </em>2 respectively. <em>P. guineense </em>was the least inhibitory. However, <em>B. cereus </em>1 was more sensitive (inhibition zone of 12 to 24 mm) to the essential oils of the spices than <em>B. cereus </em>2 (inhibition zone of 10 to 17 mm). The higher the concentration of the essential oils the greater the resultant zones of inhibition. The spices especially <em>A. melegueta</em> have proved very efficient in the inhibition of <em>B. cereus </em>a pathogen obtained from vegetable salad. The spices can therefore help in ensuring food safety.</p>
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 teacher head, 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".