**15. Conclusion**

Natural materials should be considered as potential alternative. Owing to the new attraction for natural products like essential oils and plant extracts, despite their wide use, it is important to develop a better understanding of their mode of biological action for new applications in human health, agriculture and the

*Essential Oils - Bioactive Compounds, New Perspectives and Applications*

[198] investigated the ability of *Eremophila duttonii* and *E. alternifolia* to control the growth of *L. monocytogenes* in full cream milk, skim milk, diluted homogenates of salami, pate and brie cheese, and reported that both the extracts inhibited the growth of *L. monocytogenes* in salami at 37°C, only *E. duttonii* extract was effective in pate at 4°C storage, and growth of *L. monocytogenes* was not affected by both the extracts in other products. Reduction in microbial load by water-soluble extract from pine needles of *Cedrus deodara* in fresh-squeezed tomato juice [199] and by the extracts from cinnamon stick, oregano, clove, pomegranate peel and grape seeds in raw pork over 9 days storage at ambient temperature was reported by Shan

The identification and evaluation of natural products for the control of pathogens and to assure consumers a safe, wholesome and nutritious food supply is a challenge. The problem of microbial resistance is growing and the outlook for the use of antimicrobial drugs in the future is still uncertain. Even though pharmacological industries have produced a number of new antibiotics in the last few decades, resistance to these drugs by microorganisms has increased. Plants contain thousands of constituents and are valuable sources of new and biologically active molecules possessing antimicrobial properties. The current focus in natural preservatives is on a small number of antimicrobial agents, which have been used for many years, and there is a need to expand this list for their food application to ensure safety and quality of the food products. There is no shortage of candidates to become the food preservatives of the future, but still many obstacles exist on the road to all-natural preservation. There are very few natural antimicrobials that can be used as direct replacements for existing preservatives owing to their lower effectiveness, higher cost and product organoleptic quality deterioration. Further, if a natural antimicrobial with potential as a food preservative can be shown to be sufficiently effective in foods, it will need regulatory approval before it can be used as a food additive. Once declared additive on the label, consumers will have different perspectives about these antimicrobials, but it is possible to classify them as processing aids, thus consumer perception of them being an additive can be avoided. Therefore, for the successful exploitation of the natural antimicrobials as food preservatives, probably it will not only require changes in legislation but also

The information available to date demonstrates that different antimicrobials of plant origin can effectively reduce or inhibit pathogenic and spoilage microorganism, and thus have a potential to become a good alternative to synthetic antimicrobials. The development of cost effective isolation and purification procedures that avoid loss of functional properties of active compounds will aid in wider use and acceptance of plant extracts as natural preservatives. However, too much focus on the use of single compounds over mixtures may not be compatible with complex plant extracts in which valuable bioactive molecules are often present in mixed form and the biological activity of plant extracts mostly results from additive or synergistic effects of these components. Further, the use of natural antimicrobials in combination with another or with other technologies in a multi-hurdle preservation system can enhance the performance of natural antimicrobials. Studies have demonstrated that natural antimicrobial agents may offer unique advantages for food processing, and in addition to improving the shelf life and safety of foods; they may allow novel food products with enhanced quality and nutritional properties. The applications of natural antimicrobial agents are likely to grow steadily in the future

**170**

et al. [130].

**14. Future potential**

require better consumer education.

environment. To preserve food safely and to prevent human beings from various degenerative diseases we can use essential oils as natural antioxidants and antimutagenic preferably over synthetic. Essential oils can be incorporated into rinses or mouth washes as antibacterial to protect from infection and for general improvement of oral health. The essential oils have also shown good antiviral activity but antiviral activity against the major viruses of twenty-first century such as HIV and hepatitis C viruses should also be studied. As the essential oils and plant extracts have useful biological properties, so their uses in food and pharmaceutical industry should be more as natural ingredients instead of synthetic chemicals, to save and protect the ecological equilibrium.
