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ANNUAL CONFERENCE :: Abstract Library
Abstract Library
2003 Conference Abstract
| Type of Submission |
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Submission Type: |
Poster Presentation |
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Subject Category: |
Structure and Function |
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| Session Information |
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Presentation Date: |
May 26, 2003 |
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Abstract ID: |
F8 |
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Session: |
Poster 1 |
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Time: |
14:00 |
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| Presenting Author |
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| Other Authors |
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M.J. GAGNÉ, University of Montreal
S. MESSIER, University of Montreal
G. PIETTE, Food Research and Development Center
L. SAUCIER, Food Research and Development Center
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| Title |
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Antimicrobial effect of oregano and thyme essential oils on a meat-borne strain of
Escherichia coli O157:H7.
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| Abstract Text |
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In recent years, consumer’s demand is directed towards more natural, high quality and minimally processed foods. The mode of action of all new processing alternatives developed must be understood in order to be used to their full potential. For centuries, spices and herbs have been added to food commodities for preservation and for their sensory-enhancing properties. Essential oils extracted from them have shown interesting antimicrobial properties and several active compounds have been identified (e.g., thymol, carvacrol, allyl-isothiocyanate). The Maximum Concentration Tolerated (MCT) of 11 different essential oils was tested as a colloidal starch suspension in agar medium against a meat-borne strain of Escherichia coli O157:H7. Essential oil of oregano and thyme were the most effective ones with a MCT of 0,025 %. Furthermore, cellular enumeration and viability determined using a differential detection kit (LIVE/DEAD BacLight kit, Molecular Probe, Eugene, OR) suggest that the oils are bactericidal. Transmission electron microscopy reveals that the external cortex of the cell is affected after exposition to essential oils. The cell surface becomes smooth and denser, and the periplasmic space is reduced in size. These results support earlier observations that the membranes are most likely the affected structure due to the lipophilic nature of essential oils. |
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