Antimicrobial activities of
extracts from several types of plants used today as seasoning agents in foods and beverages have been recognized for centuries. A well known early use of
plant extracts (i.e.,spices and oils) as antimicrobials was by the ancient Egyptians, who used these materials for the preservation of food stuffs as well as for embalming the dead. Garlic
extract is known to have curative effect for a variety of ailments, including indigestion, pneumonia, wounds and infections. Although ancient civilizations recognized the antiseptic or
Antimicrobial potential of many plant extracts, it was not until the eighteenth century that scientific information came to light documenting the
preservative effects of
spices and spice-type extracts.
Researchers investigating the antimicrobial activity of plant extracts used as seasoning agents have continued. In modern food processing, spices are added to foods primarily as flavouring agents. The major properties like flavor, aroma and antimicrobial factors of a
spice reside is in its essential oil. As a rule, spice essential oils are obtained commercially through distillation processes. Oleoresins, crude spice extracts with or without an organic carrier, are also commercially available and generally contain a higher concentration of essential oil than the spice itself. Spices and herbs contain a large number of compounds that are known to inhibit various metabolic activities of bacteria, yeasts and moulds. These compounds may be lethal to microbial cells or they may simply inhibit the production of a metabolite, example mycotoxins.
The use of spices, herbs and their essential oils as preservatives however is limited by the incompatibility of aromatic and flavour characteristics associated with their application to foods. The recent increased demand for minimally processed, extended shelf-life foods have renewed interest in exploitation of these natural antimicrobials for food preservation uses.
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