Interactions of Ziziphora clinopodioides and Mentha spicata essential oils with chitosan and ciprofloxacin against common food-related pathogens

The aim of the present study was to evaluate the interactions of Ziziphora clinopodioides and Mentha spicata essential oils with chitosan and ciprofloxacin against common food-related pathogens (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Listeria monocytogenes, Salmonella typhimurium and Escherichia coli O157:H7). The chemical compositions of the essential oils were identified by gas chromatography coupled with mass spectrometer detector (GC MS). The checkerboard method was used to examine the antibacterial activities of combinations of the essential oils, chitosan and ciprofloxacin by means of the fractional inhibitory concentration indices (FICI). Carvacrol (65.22%), thymol (19.51%), p-cymene (4.86%) and gamma-terpinene (4.63%) were the main chemical components of Z. clinopodioides essential oil. The most abundant constituents of M. spicata essential oil were carvone (78.76%), limonene (11.50%) and beta-bourbonene (11.23%). Based on an overall consideration of antibacterial activities, the synergetic activities were found in majority of combinations against tested microorganisms. No indifference and antagonism activity was observed for any of the combinations designed. According to the results of the present study, Z. clinopodioides essential oil in combination with M. spicata essential oil and chitosan could be considered as practical potential strong antimicrobials in food products. (C) 2016 Elsevier Ltd. All rights reserved.