Application of Essential Oils as Natural Preservatives in Meat Products
Bedika Bora
Department of Livestock Products Technology, ICAR- Indian Veterinary Research Institute, Izatnagar (Uttar Pradesh- 243122)
Email id- bedikabora@gmail.com
SUMMARY
Meat and meat products are widely consumed by consumers as a source of protein. But these products tend to spoil easily when preservative conditions are not maintained. Some spoilage and pathogenic microorganisms are the main contaminants in meat and meat products which considerably impact meat quality and safety. Nowadays, chemical preservatives are generally used in industrially processed foods to increase their shelf life. However, these preservatives may have a negative effect on consumers’ health due to their possible toxicological effects. Recently, research has shown the potential of using essential oils as a preservative for meat products. Essential oils are extracted from natural plant sources and they offer an alternative to consumer demand for healthy foods with a more natural appeal. In addition, essential oils can be extracted from a great diversity of plants, whose antimicrobial activity in vitro and in meat and meat products have been proven. Application of essential oils is partially limited due to their intense aroma but advanced technologies can be combined to improve both the microbial stability and sensory quality of finished product.
INTRODUCTION
Meat is considered as one of the main sources of protein in human food. Due to their complex chemical composition, meat is highly susceptible to contamination by microorganisms, which results in higher risk of occurrence of food-borne diseases. Therefore, it is challenging for the manufacturers to produce safe and high quality meat and meat products that can also meet the consumers’ demand for natural and clean-label food.
In recent times, the use of plant-derived essential oils as a source of preservative is gaining popularity. They have shown remarkable antimicrobial potency against spoilage and pathogenic microorganisms found in meat and meat products. Essential oils can replace synthetic preservatives considering they are obtained naturally and thus are considerably safer as they have been classified as “generally recognized as safe or GRAS” by Food and Drug Administration (FDA). At the same time, studies have shown that these essential oils can enhance, either directly or indirectly, the functional value of meat products.
What are essential oils?
Essential are natural, volatile and aromatic liquids extracted from some plants such as cinnamon, cloves, oregano, etc. They are a complex mixture of secondary metabolites such as terpenes, alcohol and phenolic compounds. They possess a wide range of biological activities including antimicrobial, antioxidant and anti-inflammatory properties. Particularly, they exhibit pronounced antibacterial and food preservative properties that have represented a real potential for meat industry. 3000 essential oils approximately produced by plants of different genera have already been identified, out of which only approximately 300 of these are considered to be of commercial value.
Antimicrobial activity of essential oils
The antimicrobial activity of essential oils is due to the presence of secondary metabolites. The hydrophobic components present in these metabolites interact with the lipids present in the cell membrane of spoilage microorganism (da Silva et al., 2021). This interaction causes loss of membrane integrity of spoilage microorganisms and this damage induces changes in the functioning of the electron transport chain, in the coagulation of cellular content in the absorption of nutrients, in both protein and nucleic acid synthesis, and in the inhibition of enzymes essential for energy metabolism, causing cell death.
Essential oils even in low concentrations can cause significant changes in sensory quality of food. Increased concentration of essential oil in meat and meat products may negatively influence sensory acceptance due to differences in oil bioactivity in food systems, limiting their application (da Silveira et al., 2014). To overcome these problems, nanoparticles such as cyclodextrin , liposomes, silicon dioxide and nanoemulsion, along with packaging methods such as food wraps and nanofibers have been used as effective encapsulation systems to protect the essential oils in food system.
Recent studies in application of Essential oils in meat products
Bacteria of the genera Pseudomonas, Staphylococcus, Acinetobacter, lactic acid bacteria (LAB), Moraxella, Brochothrix, Flavobacterium, Micrococcus and different genera of the Enterobacteriaceae family are associated with the deterioration and contamination of meat and meat products. These contamination can occur throughout the production chain, especially during slaughter, processing, distribution and storage processes.
The efficiency of essential oils against a particular spoilage microorganism depend on many factors such as the extraction methods used, the mechanisms of action against specific microorganisms, the interaction of the constituents with the food system, etc. Several studies have conducted to study the antimicrobial activity of essential oils in meat and meat products with promising results. Some of the recent studies have been summarized in Table 1.
Table 1: Recent Studies in Application of Essential Oils in Meat and Meat Products.
| Essential oils extracted from plant sources | Food | Essential oil ioncentration | Microorganisms | Observations | References |
| Cinnamon bark (Cinnamomum cassia) | Ground lamb meat | 0.01, 0.025, 0.05 and 0.5% (v/w) | Total viable counts; LAB and Enterobacteriaceae | Comparing to control, in samples with 0.5% EO the LAB population had a reduction of 0.6 to 1.9 log CFU/g from the 4th to the 16th day of storage. The highest concentration of EO reduced the population of Enterobacteriaceae to 0.9 and 1.1 log CFU/g on days 12 and 16, respectively, when compared to the control samples. | (Hussain et al., 2021) |
| Oregano (Origanum vulgare) and rosemary (Rosmarinus officinalis) | Tuscan sausage | 0.05, 0.1, 0.2 and 0.4% (w/w) | LAB | The LAB population of the samples with 0.4% oregano and rosemary EO extended the sausage’s shelf life to 47.84 days according to the LAB growth limit: 7 log CFU/g. The control sample achieved this limit in 28.35 days of storage. | (Badia et al., 2020) |
| Nutmeg (Myristica fragans) | Beef | 0.5, 1.0, 1.5 and 2.0% (v/w) | Total viable count, psychrotrophic bacteria; E. coli, S. aureus and mold | Meat samples coated with 2.0% EO + sage seed mucilage had an increase of 6 days in its shelf life, in addition to a significant suppression in the growth of the tested microorganisms. | (Kiarsi et al., 2020) |
| Tea tree (Melaleuca alternifolia) | Ground beef | 1.5% (v/w) | L. monocytogenes | Samples inoculated with a cell culture suspension of 3.06 and 3.96 log CFU/g did not present growth after the first 20 min of storage. Tea tree EO was not effective in samples inoculated with suspensions of 8.17 log CFU/g, independent of storage time. | (de Sá Silva et al., 2019) |
| Clove (Syzygium aromaticum ) | Hamburger | 3.04 × 10− 8 to 3.04 × 10− 7 % (w/v) | S. aureus | The in situ antimicrobial activity of clove EO against S. aureus was superior to that of sodium nitrite. | (Radünz et al., 2019) |
Limitations in use of essential oils as natural antimicrobial in meat products
In case of in vitro research, essential oils have shown excellent results as preservative agents due to its antimicrobial activity. But when applied in food systems, the bioactivity and efficiency of essential oils reduces considerably, requiring concentrations that can vary from 10 to 100 times than the value obtained in vitro. This is probably due to the presence of lipid constituents, proteins and other compounds in food system that can interact with essential oils and decrease their availability to act against microorganisms. Meat nutrients can also favor the recovery of microorganisms that have suffered some type of injury and stress due to the antimicrobial action of essential oils.
To combat these problems, a combination of different essential oils or encapsulation can be a viable alternative to increase the antimicrobial effect of essential oils without significantly altering the sensory properties of the food (Ghaderi-Ghahfarokhi et al., 2017). Recent studies have also been conducted to use nanoemulsion method, such as the recent use of nanoemulsion containing star anise essential oil (Illicium verum), nisin and polynisine as coating material on a pork product which resulted in increased shelf life of the product along and improved sensory attributes and consumer acceptance (Liu et al., 2021).
CONCLUSION
Essential oils can be used as an alternative in industrially processed meat products due to their natural appeal for consumers who demand healthy and safe foods. One of the main challenges in applying essential oils as natural preservative would be the development of modern technologies for incorporating essential oils in finished product in order to minimize any sensory changes, improve their antimicrobial properties and contribute to the improved food quality. In this sense, several studies are ongoing on encapsulation method with controlled release of essential oil, synergistic combinations of different essential oils, incorporation into active packaging, edible coatings, and hurdle technology as well as the application of models to predict the toxicity of constituents of essential oils and the behavior of these compounds under different processing conditions. This area has extensive field for the development of new scientific research, given the diversity of plant sources from which these oils can be extracted.
REFERENCES
Badia, V., de Oliveira, M. S. R., Polmann, G., Milkievicz, T., Galvão, A. C., & da Silva Robazza, W. (2020). Effect of the addition of antimicrobial oregano (Origanum vulgare) and rosemary (Rosmarinus officinalis) essential oils on lactic acid bacteria growth in refrigerated vacuum-packed Tuscan sausage. Brazilian Journal of Microbiology, 51(1), 289-301.
da Silva, B. D., Bernardes, P. C., Pinheiro, P. F., Fantuzzi, E., & Roberto, C. D. (2021). Chemical composition, extraction sources and action mechanisms of essential oils: Natural preservative and limitations of use in meat products. Meat Science, 108463.
da Silveira, S. M., Luciano, F. B., Fronza, N., Cunha Jr, A., Scheuermann, G. N., & Vieira, C. R. W. (2014). Chemical composition and antibacterial activity of Laurus nobilis essential oil towards foodborne pathogens and its application in fresh Tuscan sausage stored at 7 C. LWT-Food Science and Technology, 59(1), 86-93.
de Sá Silva, C., de Figueiredo, H. M., Stamford, T. L. M., & da Silva, L. H. M. (2019). Inhibition of Listeria monocytogenes by Melaleuca alternifolia (tea tree) essential oil in ground beef. International journal of food microbiology, 293, 79-86.
Ghaderi-Ghahfarokhi, M., Barzegar, M., Sahari, M. A., Gavlighi, H. A., & Gardini, F. (2017). Chitosan-cinnamon essential oil nano-formulation: Application as a novel additive for controlled release and shelf life extension of beef patties. International journal of biological macromolecules, 102, 19-28.
Hussain, Z., Li, X., Zhang, D., Hou, C., Ijaz, M., Bai, Y., … & Zheng, X. (2021). Influence of adding cinnamon bark oil on meat quality of ground lamb during storage at 4° C. Meat Science, 171, 108269.
Kiarsi, Z., Hojjati, M., Behbahani, B. A., & Noshad, M. (2020). In vitro antimicrobial effects of Myristica fragrans essential oil on foodborne pathogens and its influence on beef quality during refrigerated storage. Journal of Food Safety, 40(3), e12782.
Liu, T., Kang, J., & Liu, L. (2021). Thymol as a critical component of Thymus vulgaris L. essential oil combats Pseudomonas aeruginosa by intercalating DNA and inactivating biofilm. LWT, 136, 110354.
Radünz, M., da Trindade, M. L. M., Camargo, T. M., Radünz, A. L., Borges, C. D., Gandra, E. A., & Helbig, E. (2019). Antimicrobial and antioxidant activity of unencapsulated and encapsulated clove (Syzygium aromaticum, L.) essential oil. Food chemistry, 276, 180-186.
