Fully dilutable Thymus vulgaris essential oil:acetic or propionic acid microemulsions are potent fruit disinfecting solutions

The aim of this study was to evaluate the effect of acetic (AA) or propionic (PA) acid as a cosurfactant on the microemulsion (ME) characteristics of Thymus vulgaris essential oil (TVO). The results showed that addition of propylene glycol to TVO/AA or PA:T80/water MEs gave dilutable systems with particles similar to 59 nm in diameter. Plain TVO showed the highest antimicrobial activity against E. coli, S. aureus, and S. typhi in in vitro antimicrobial tests, followed closely by AA/PA-MEs. The antimicrobial activity of AA/PA-MEs used as a washing solution on cucumber and strawberry samples was remarkably greater than those of free TVO, TVO nanoemulsions, and chlorhexidine solutions against E. coli and S. aureus. The sensory properties of the samples were not changed by the use of AA/PA-MEs at 0.05 or 0.1% TVO. The results introduce dilutable TVO:AA/PA-MEs for incorporation of TVO in aqueous systems for use as a fruit/vegetable disinfecting agent.

Automated summary

The study found that AA/PA-MEs can be used as washing solutions with higher antimicrobial activity than free TVO and TVO nanoemulsions for disinfecting cucumber and strawberry samples. Additionally, the sensory properties of the samples were not significantly altered when AA/PA-MEs were used.