In this study, the minimum inhibitory concentration (MIC) of oleuropein (OLE), a phenolic compound extracted from Oliveira leaves, alone or in combination with commercial sanitizers, was determined for Listeria monocytogenes (ATCC 7644), Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). MIC values were determined using individual suspensions containing nearly 108 cells/mL of each bacterial species treated with serial dilutions of OLE (0.4 mg/mL) and commercially available solutions of Peracetic acid (PAA, 2.0%), Benzalkonium chloride (BC, 1.0%), Chlorhexidine digluconate (CD, 2.0%), Sodium hypochlorite (SH, 2.0%) and Hydrogen peroxide (HP, 3.0%). OLE had low inhibitory activity (0.2 mg/mL). As expected commercial sanitizers showed high bactericidal activity according to MIC values. However, the association of OLE with commercial sanitizers increased their bactericidal effect, especially for CD, which combination with OLE resulted in approximately 60-fold reduction in the MIC values for S. aureus and L. monocytogenes. OLE and BC also led to nearly 30-fold or 10-fold reductions of MIC values for S. aureus and L. monocytogenes, respectively. The combination of PAA and OLE reduced the MIC values for E. coli and S. aureus by 10-fold, with little effect on L. monocytogenes. Results of this preliminary study indicate that OLE has the potential to enhance the bactericidal effect of commercial sanitizers, especially against L. monocytogenes and S. aureus. Further studies are necessary to understand the mechanisms of action of these combinations.
Citation: Dominciano LCC, Oliveira CAF, Lee SH, Corassin CH. 2016. Individual and Combined Antimicrobial Activity of Oleuropein and Chemical Sanitizers. J Food Chem Nanotechnol 2(3): 124-127