Medicinal plants, natural colour and spices were examined in vitro for antibacterial effects on the growth of Escherichia coli (EPEC) serotype O:125, Salmonella thyphimurium, Staphylococcus aureus, Listeria monocytogenes ATCC 7644 and Yersinia enterocolitica ATCC 9610. The most effective medicinal plant was Lippia sidoides at concentration of 3 percent (w/v), that added to Trypticase Soya Broth completely inhibited the growth of S. thyphimurium, S. aureus, L. monocytogenes and Y. enterocolitica. Among the spices, the cloves (Sysygium aromaticum) extract had the strongest inhibitory activity on the growth of E. coli, S. thyphimurium e Y. enterocolitica demonstred through the agar difussion technique. Sage (Salvia officinalis) and rosemary (Rosmarinus officinalis) extracts inhibited the growth of L. monocytogenes and S. aureus. The nutmeg (Myristica fragrans) extract also prevented the development of L. monocytogenes.