spice essential oils prevent bacterial growth
Antibacterial efficiency of Finnish spice essential oils against pathogenic and spoilage bacteria.Nevas M1, Korhonen AR, Lindstr?m M, Turkki P, Korkeala H.
- 1Department of Food and Environmental Hygiene, Faculty of Veterinary Medicine, 00014 University of Helsinki, Finland. email@example.com
AbstractThe antibacterial properties of 13 essential oils, derived from spices grown in Finland, were examined with an agar diffusion method against 12 bacterial strains. The organisms tested included both spoilage and pathogenic bacteria. The gram-positive bacteria appeared to be more sensitive than the gram-negative organisms, Clostridium botulinum and Clostridium perfringens being the most sensitive. Oregano, savory, and thyme showed the broadest antibacterial activity by distinctly inhibiting the growth of all the organisms tested. By gas chromatography-mass spectrometry analysis, differences were noted in the composition of oregano and thyme oils in comparison to previous reports.
Spices are aromatic plant products that are used in flavoring foods and beverages. They are known to provide a wide range of compounds with antimicrobial activity, which is mainly associated with the fraction of volatile essential oils. Essential oils could serve as potential antibacterial agents, thus prolonging the shelf life of certain food products. They might also provide alternatives to food additives, such as nitrite, that potentially have undesirable effects on human health(20).
The antimicrobial and antifungal efficiency of different plant essential oils has been studied previously (3, 4, 6, 7, 11-13). However, it has been reported that the antimicrobial properties can vary within the same plant species because the chemicial composition and relative proportions of the individual constituents in the essential oils of the plants are influenced by genotype, growth stage, drying, climate, and geographical location (2, 15, 19). The antimicrobial activity of oregano, savory, and thyme is likely due to their high content of thymol and carvacrol, which are among the most efficient herbal antibacterial agents known (7, 18). It has also been noted that the production of phenolic compounds increases under warm, dry conditions (13).
In the present study, the efficacy of certain spice essential oils in preventing growth of several bacterial strains was evaluated in vitro. All the oils studied are derived from herbs grown in latitudes 60 and 70 degrees North in Northern Europe. It is thus possible to assess the influence of this northern climate with its relatively short growing period and moderate rainfall on the antibacterial activities of these oils. The thermal growth period in the production area of the herbs lasts approximately 140 to 175 days, but the persistence of snow in spring can shorten the period further by 2 to 3 weeks. On the other hand, the time period between sunrise and sunset is extended, varying from 15 to 19 h during June, July, and August in southern Finland. There are 73 so-called solar days per year in northern Finland, during which the sun does not set below the horizon at all. The mean summer temperatures were approximately 14 to 16 degrees C in the area where these spices were grown.
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