Olive leaf extract shows antibacterial properties

A new study found that Euromed’s olive leaf extract inhibits the growth of Listeria monocytogenes bacteria.[1] Olive leaf extract has traditionally been used as a herbal dietary supplement as it contains oleuropein and other polyphenolic compounds that offer blood pressure, heart health and immune system benefits. In addition to enhancing human health, olive leaf extract may also be used as an antimicrobial to control potential foodborne pathogens.

Secondary plant substances such as olive leaf extract are gaining increasing attention as potential antibacterial and food preservative agents. These naturally occurring compounds possess diverse chemical structures, a wide range of biological activities, and are in line with consumer trends seeking foods produced with natural ingredients.

That olive leaf extract has antimicrobial properties is good news for manufacturers challenged by the growth of Listeria monocytogenes in dairy, ready-to-eat, and other foods. (Photo by Tomo Jesenicnik I Dreamstime.com)

Olive leaf extract shows promising effects as an antimicrobial agent to control Listeria monocytogenes in foods. These foodborne pathogens, often found in dairy products, vegetables and ready-to-eat foods, can survive and grow in harsh conditions such as low temperatures. As such, the elimination of these bacteria is a significant challenge for the food industry.

In the current study, Dr. Yanhong Liu and other researchers synthesized gold nanowires using bacterial flagella as a template. Gold nanowires are highly effective catalysts that improve the efficiencies of secondary plant metabolites as bacterial inhibitors. The researchers found that olive leaf extract inhibits the growth of Listeria monocytogenes completely. In addition, the gold nanowires demonstrated high electrocatalytic activity and showed no mutagenic effect at the concentration used. Therefore, the gold nanowires fabricated in this work have the potential to be used as new antimicrobial packaging materials to enhance food safety.

In a previously published study, Dr. Yanhong Liu and others investigated the antimicrobial effect of olive leaf extract against major foodborne pathogens, including Listeria monocytogenes, Escherichia coli and Salmonella enteritidis.[2] The results demonstrated that at a concentration of 62.5 mg/ml, olive leaf extract almost completely inhibited the growth of these three pathogens. In addition, it also inhibited biofilm formation in Listeria monocytogenes and Salmonella enteritidis, and reduced cell motility in Listeria monocytogenes.