Developing Highly Diluted Alcoholic Sanitizers Loaded with Eugenol and Cinnamaldehyde as Antibacterial Boosters for Controlling Some Pathogenic Bacteria

The authors aimed at developing novel diluted hydro-alcoholic sanitizer containing significantly lower content of alcohol. Antibacterial boosters like eugenol and cinnamaldehyde were used in the developed formula to compensate for the low alcohol content. The maximum water content and the solubility (miscibility) of eugenol and cinnamaldehyde in the diluted alcoholic formula was investigated using the Gibbs' phase diagrams. The broth dilution assay was used to evaluate the growth inhibition of the developed sanitizing formula against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli and Pseudomonas aeruginosa. Results indicated that a homogenous highly diluted hydro-alcoholic formula can be achieved using only 22.5% alcohol (isopropanol), 75% water and up to 2.5% eugenol. On the other hand, cinnamaldehyde showed different attitude, where the maximum dilution of alcohol that can be reached is 37.5% with 60 % water and up to 2.5% cinnamaldehyde. Evaluation of the antibacterial activity of the two formulas showed complete inhibition of the growth of the tested pathogens, where the count after treatment was zero cfu/ml. This antibacterial activity was similar to that of commercial hydro-alcoholic sanitizer that contains 70% alcohol. The study represents an insight towards an applicable alcoholic sanitizer characterized by significantly lower content of alcohol without compromising efficiency.