Bactericidal effectiveness of active chlorine solution with essential oils

Abstract

Insufficient hygiene of food contact surfaces often leads to food contamination with bacteria that cause foodborne diseases in humans, which is a growing public health problem and causes large economic losses, despite modern improvements in food production and preservation techniques. The use of natural substances with antimicrobial activity, such as essential oils, is an environmentally friendly and effective way to control the presence of potentially pathogenic bacteria. These agents are increasingly used in combination with conventional antimicrobial agents. Therefore, the aim of this study was to examine the antimicrobial activity of essential oils namely Lavandula officinalis (lavender), Melaleuca alternifolia (tea tree), Menthae piperitae (mint) and Rosmarinus officinalis (rosemary), and active chlorine solution (0.1%) (Aqualor H1000, Sigma d.o.o., Crvenka) against two gram-positive bacteria Bacillus cereus ATCC 11778 and Staphylococcus epidermidis ATCC 12228, and two gram-negative bacteria Pseudomonas aeruginosa ATCC 10145 and Salmonella Typhimurium ATCC 14028, as well as to evaluate the antimicrobial activity of essential oils and active chlorine solution (0.1%) mixed in different combination (FIC) in order to detect synergistic or antagonistic effects and discuss these effects (FICI, FIC index) on the basis of an improved checkerboard technique. The results showed a synergistic and additive effect for most combinations of active chlorine solution and essential oils. While with the reference strain P. aeruginosa ATCC 10145, an indifferent effect was observed in the combination of active chlorine solution with essential oils of mint and rosemary. The effectiveness of the solution of active chlorine with essential oils was determined using the quantitative suspension test according to the DGHM method. The results indicated that the maximum germicidal effect of the solution was achieved after exposure for 5 minutes for all tested bacteria. The lowest degree of reduction was recorded against B. cereus ATCC 11778 and S. Typhimurium ATCC 14028 at the shortest exposure time of 1 minute, while a stronger effect was recorded against S. epidermidis ATCC 12228 and P. aeruginosa ATCC 10145. Taking into account that there has been an increased interest in the use of natural antimicrobial agents in recent years, the application of a combination of active chlorine with essential oils represents a significant strategy in the control of pathogenic bacteria.