A new report shows that essential oils derived from plants have antibacterial properties and could potentially act as natural preservatives in meat.
Plant-derived essential oils have the potential to replace chemical preservatives in meat products against bacterial contamination, according to a new study.
The findings, published in the Frontiers in Nutrition journal, showed that essential oils derived from plants have antimicrobial properties from its bioactive components like phenolic acids, terpenes, aldehydes and flavonoids.
The researchers reviewed the capability of plant essential oils in mitigating or inhibiting the growth of the bacteria L. monocytogenes, a pathogen found commonly in meat products. It causes listeriosis, which is a foodborne illness with high rates of mortality and hospitalisation; and it usually occurs due to the consumption of contaminated meat.
L. monocytogenes can survive and grow in both raw and cooked meat, and tolerate low-oxygen conditions, nitrite and high salt content, which makes meat an ideal carrier. While some methods to terminate this bacteria include thermal treatment, high-pressure processing and using antimicrobial additives and synthetic preservatives, researchers noted that consumers are looking for more natural and safer sources like essential oils.
“In recent years, consumers have shown an increasing concern about the use of synthetic chemical preservatives. There is an increasing tendency in using natural additives including antioxidants, antimicrobials, sweeteners, and colouring agents that originated from animals, plants, and microorganisms,” read the study.
Essential oils are volatile and naturally found in different parts of plants, including seeds, roots, leaves, buds, flowers, barks, fruits and peels. There are about 3,000 known essential oils, 300 of which are used in the commercial cosmetic, food and pharmaceutical industries.
“The antimicrobial activity of essential oil may be due to the possible penetration of it through the bacterial cell wall, causing leakage of ions and other cell compounds, and when the leakages are more than the limit, cell death occurs,” the researchers said.
They added that other mechanisms include the ability to change fatty acid profiles and increase cell permeability. “Generally, the interaction of essential oils with cell membranes of bacteria can be effective in preventing bacterial growth.”
The main drawback, however, is the strong aromas of the plant essential oils, which could bring out off-flavours. That would limit its usage in high quantities, meaning a lower level of antimicrobial activity. For example, using clove essential oil (10%) could inactivate L. monocytogenes in ground beef, but researchers found that consumers didn’t welcome that due to the strong clove flavour in the meat. To solve that, one solution suggested was to combine the essential oil with salt or acid and build proper storage conditions.
