Food for human consumption is often preserved in some manner to slow or prevent autolytic degradation or undesirable changes caused by oxygen, light, or the growth of spoilage microorganisms. Some of the same preservation processes used to control growth of spoilage microorganisms may also improve food safety by inhibiting or inactivating pathogenic or disease-causing microorganisms. The use of chemical antimicrobials to preserve foods increased significantly in the twentieth century. Spices and herbs are generally used for flavoring agents in foods, however they are known to contain essential oils (EOs) and essential oil components (EOCs), some of which are known to possess antimicrobial activity. A number of potential issues must be addressed in determining whether EOs or EOCs can be successfully applied to foods for use as antimicrobials, including toxicological effects, cost, influence of food components on activity and sensory effects.