Today, the use of natural antibiotics is increasing due to microbial resistance to chemical antibiotics as well as their side effects. Many plants have antibacterial compounds. Previous studies have shown that saffron extract had antibacterial effects on some bacteria. In addition, the use of nanoparticles to improve the antibacterial effects of antibiotics has been shown in previous studies. The aim of this study was to investigate the possible antibacterial effects of a hydro-alcoholic extract of saffron and chitosan nanoparticles loaded with the extract against E. coli strain H7O157 and comparing the effects with each other. To determine the antimicrobial effects of saffron extract and its formulated extract, the minimum inhibitory concentration (MIC) was obtained by the tube dilution method. Three doses of saffron extract and three doses of saffron formulated extract were added to six tubes containing bacterial suspension. Two tubes were considered as a positive control (extraction plus culture media) and negative control (microbial suspension plus culture medium). The results of this study showed that both saffron extract and its formulated extract in chitosan had antibacterial effects against E. coli strain H7O157. In addition, the MIC of a formulated extract of saffron was less than the non-formulated extract.
