Oregano is an important culinary and medicinal herb that has been used in medicine and cooking for thousands of years - with a number of health benefits. It is a species of Origanum, belonging to the mint family (Lamiaceae). It is an indispensable spice in Turkish, Greek, Portuguese, Spanish, Latin American and Italian cuisine, oregano is the must-have ingredient in tomato sauces and pairs well with capers and olives.
It is one of the top five spices in the world with one of the highest ORAC (Oxygen Radical Absorbance Capacity) scores meaning it will more effectively neutralize free radicals. It is a powerful antimicrobial.
Oregano has shown antimicrobial activity in a number of studies. A group of Portuguese researchers found that Origanum vulgare essential oils were effective against 41 strains of the food pathogen Listeria monocytogenes.
Writing in LWT- Food Science and Technology , researchers revealed that exposing the bacterium Staphylococcus aureus (a frequent cause of food poisoning) to either the essential oil of the oregano plant Origanum vulgare L. (OVEO) or carvacrol (a phenolic compound found in OVEO) reduced the number of bacterial cells stuck to food preparation surfaces.
S. aureus is a pathogenic bacterium underlying many instances of food poisoning worldwide. It is able to survive by its ability to form robust biofilms, which resist most attempts to remove the bacterium from food preparation surfaces, explained the researchers from the Federal University of Paraiba, Jose Pessoa, Brazil.
The study findings therefore highlight the potential of OVEO and carvacrol as novel anti-bacterial agents, which could be used in the fight against food poisoning in food preparation environments, said the team.
Furthermore, both the oregano-derived treatments performed more effectively than sodium hypochlorite (NaClO) a 'conventional' means of removing pathogenic bacteria from stainless steel surfaces.
"OVEO and carvacrol could be considered potential substances to replace classical agents, primarily NaClO, used to disinfect stainless steel surfaces in the food industry," commented senior author Marciane Magnani.
OVEO and CAR also had the advantage of not causing corrosion damage to the surfaces, unlike NaClO, the study showed.
A ten minute exposure to either ten microlitres/millilitre (microL/mL) of OVEO or five microL/mL carvacrol was enough to reduce the number of cells on the surfaces by over 100-fold for both strains of S. aureus tested.
After 15 minutes, the same concentrations of OVEO and carvacrol virtually eradicated one strain of the bacteria to undetectable levels, however only carvacrol was effective in eliminating the both strains.
Indeed, carvacrol, the concentrated active ingredient of OVEO, was found to be more effective than the essential oil itself and was able to create holes in the cell membranes of S. aureus cells.
"The results of this study indicated that carvacrol and OVEO are effective agents to remove young and mature S. aureus biofilms on stainless steel surfaces. OVEO and carvacrol were more effective than NaClO to remove S. aureus biofilms on a stainless steel surface, while causing no damage on these surfaces, as did NaClO," said Magnani.
"Carvacrol was more effective than OVEO because the later failed to eliminate the young and mature biofilms of one (S. aureus LPMA11) of the two strains tested," she added.
Food Science and Technology