Green synthesis of ZnO nanoparticles from Foeniculum vulgare Mill. seed extract and its antibacterial effects on foodborne bacteria

Foeniculum vulgare Mill. seeds contain polyphenolic compounds which can be considered a suitable option for the green synthesis of nanoparticles.

In this study, the antibacterial activity against foodborne bacteria of ZnO nanoparticles synthesized from the aqueous extract of Foeniculum vulgare Mill. seeds was evaluated.

The synthesized ZnO nanoparticles were characterized using different analyses. The minimum inhibitory and bactericidal concentration of the nanoparticles were investigated against standard foodborne bacteria, S. aureus, Y. enterocolitica, E. coli O157:H7, and B. cereus, using the broth microdilution method.

UV-Vis spectroscopy analysis indicated an absorption peak at 231 nm which confirms the formation of ZnO nanoparticles. In addition, the X-ray diffraction pattern is consistent with the JCPDS cards, which also means the formation of ZnO nanoparticles. The results of the electron microscope revealed that the nanoparticles had a hexagonal shape with an average size of 50 nm, which is in agreement with the results obtained from the dynamic light scattering analysis. In addition, the minimum inhibitory concentration of ZnO nanoparticles against gram-negative and gram-positive bacteria, Y. enterocolitica, E. coli O157:H7, S. aureus, and B. cereus were 62.5, 62.5, 31.25 and 500 µg/ml, respectively.

ZnO nanoparticles synthesized from Foeniculum vulgare Mill. seed extract had an appropriate antibacterial effect against foodborne bacteria.