Phytosynthesis of selenium nanoparticles using the costus extract for bactericidal application against foodborne pathogens

Selenium (Se) as a bioactive micronutrient could be augmented via transforming into nanoparticles (NPs), especially using biogenic protocols, for usage as an antimicrobial element. The reducing power of costus (Saussurea costus) root extract (SCE) was employed for phytosynthesis of Se-NPs through a simple and rapid protocol that included stirred mixing of 10 mM Na2SeO3 with 1.0% SCE solution for 4 h. The phytosynthesized SCE/Se-NP composite was obtained with a mean diameter of 6.13 nm and a zeta potential of -42.8 mV. Infrared analyses revealed the involvement of many SCE phytogroups in Se-NP synthesis, whereas transmission microscopy displayed well distribution and spherical shapes of the phytosynthesized NPs. The antibacterial assessments against foodbome pathogens (Escherichia coli, Salmonella typhimwium and Staphylococcus aureus) revealed the superior powers of SCE/Se-NPs and the elevated potentialities of SCE and Se-NPs for inhibition of bacterial pathogens. The scanning micrographs indicated that SCE/SeNPs were attached to bacterial cells and led to their complete lysis/explosion with exposure prolongation. The SCE/Se-NP composites are recommended for the effective control of foodbome bacterial pathogens, applying a simple and ecofriendly phytosynthesis protocol.