US study finds oregano oil causes off-flavours in meat

A new study found that oregano oil may reduce lipid oxidation and extend the shelf-life of meat products, but there were adverse effects on flavour.

Conducted by researchers from Mississippi State University and the University of Kentucky, the study used beef longissimus dorsi and semimembranosus mucles from animals of various ages.

The researchers halved six muscles of each age group and enhanced them with either a control brine containing no antioxidants or a brine containing oregano oil. The meat pieces then were cut into steaks and stored in modified-atmosphere packaging for 0 days, four days, seven days and 11 days. Each sampling day the researchers measured surface colour, lipid oxidation, cook yield, sensory analysis and Warner-Bratzler shear force.

The steaks enhanced with oregano oil decreased lipid oxidation but had no effect on Warner-Bratzler shear force or sensory tenderness and juiciness scores when compared to the steaks that had no antioxidants. The steaks enhanced with oregano oil had less rancidity detection, more off-flavour and lower overall acceptability in sensory analysis.

This indicates that while oregano oil could reduce lipid oxidation, the adverse effects on flavour were too great and thus would not be tolerable in fresh meat products at this concentration, said the researchers.

However, the researchers noted there is potential to use oregano oil at lower concentrations and in a variety of processed products which could be beneficial to further the use of natural antioxidants.