Oregano essential oil as an antimicrobial additive to detergent for hand washing and food contact surface cleaning.

AIMS To investigate the potential use of oregano essential oil as an antimicrobial agent in liquid soap for hand washing and for food contact surface cleaning. METHODS AND RESULTS Oregano essential oil (O.E.O.) was emulsified in liquid detergent solution. This was challenge tested against a commercial antimicrobial soap in hand washing trials using natural flora. Soap with O.E.O. was as effective as the commercial antimicrobial soap at reducing aerobic plate count on the hands and more effective than plain soap with no additives. Cloths wetted with soap with O.E.O. were used to clean three different surfaces contaminated with four bacterial pathogens. For three of the four pathogens, the addition of 0·5% v/v O.E.O. to the soap solution enhanced cleaning performance and also reduced bacterial survival on the cloth after cleaning. CONCLUSIONS Oregano essential oil (0·5%) is effective as an antimicrobial additive to detergent solutions for hand washing and surface cleaning. SIGNIFICANCE AND IMPACT OF STUDY This preliminary study has shown that oregano essential oil is a potential alternative to antimicrobials used in various detergents, such as chloroxylenol and triclosan, which can have adverse environmental and health effects. Further development could lead to a commercial product.