Olives were supplemented with two different carbon sources (sucrose and glucose) at five different levels (0%, 0.1%, 0.3%, 0.5% and 1%) and the fermentation procedure was followed after inoculation with or without starter culture. Inhibition of Escherichia coli O157:H7 was evident in all fermentation procedures regardless of the treatment used. The pathogen numbers declined but did not die out during fermentation. It was evident that the rate of death was higher in samples supplemented with starter cultures compared to natural fermentation. The production of acids during fermentation seems to be the main factor that governs the behaviour of this pathogen under such stress conditions. The HPLC analysis revealed that lactate, formate and acetate were among the end-products during the fermentation of green olives.