Laura C. C. Dominciano, Sarah H. I. Lee, Roice E. Rosim, Carlos H. Corassin and Carlos A. F. Oliveira
University of Sao Paulo, Department of Food Engineering, Av. Duque de Caxias Norte 225, 13635- 900 Pirassununga, SP, Brazil
The development of more efficient sanitizers for reducing the biofilm formation by pathogenic bacteria is of great importance, especially in the food industry. The aim of this study was to evaluate the efficiency of oleuropein (OLE), a phenolic compound extracted from olive leaves, and peracetic acid (PAA), alone or in combination, to inactivate biofilms formed by Listeria monocytogenes (ATCC 7644). Duplicate biofilm assays were prepared in stainless steel coupons during 48 h without stirring. After, the biofilms were washed (NaCl 0.85%) and rinsed with solutions of OLE (5.0 mg/mL) and/or PAA (2.0%) for 1 min. The reaction was stopped with sodium thiosulfate 0.1 M for 5 min. The inactivation of biofilms was assessed by confocal microscopy. OLE alone in contact with biofilms had low bactericidal activity on the biofilms, when compared with PAA. However, the treatment of OLE in combination with PAA resulted in greater inactivation of biofilms. Results indicate a potential application of OLE for enhancing the bactericidal effect of PAA against L. monocytogenes biofilms, although further studies are necessary to understand the mechanisms of action of OLE in combination with commercial chemical sanitizers.
Funding: National Council for Scientific and Technological Development (CNPq, Grant # 309348/2013-7).
Keywords: L. monocytogenes, microbial biofilms, organic sanitizers.