omw ethyl acetate extracts and hydroxytyrosol inhibited Ps tolaasii Growth but did not show bactericidal activity only 4-methylcatechol and catechol were effective as bactericides against Ps tolaasii (minimum biocidal concentration 5 and 10 mM, respectively). such concentrations were not reached if the wastes were added at 10% v/w at such levels growthof the bacteria will only be inhibited not eliminated completely