Abstract: Assessing the resilience of rice varieties against bioterrorism agents is critical to safeguarding food security. This study evaluates the Food and Drug Administration (FDA)-approved and recognized as safe metallic oxide nanoparticles (NPs) of zinc oxide (ZnO) and magnesium oxide (MgO) as protective strategies for susceptibility in imported rice varieties to a biothreat model, Escherichia coli (E. coli). Two types of rice (brown and white) and four origins (USA, Mexico, India, and Thailand) were treated with 60 mg/L NPs and their ionic form (n = 3) and sterilized before inoculation. The treatments were tested for nutritional profiles, heavy metal content, and pathogen susceptibility. Rice organic compositions were characterized by Fourier-Transform Infrared Spectroscopy, and metals were quantified using Inductively Coupled Plasma Optical Emission Spectroscopy. The pathogenic response was monitored using Ultraviolet mass spectrophotometry. The findings revealed that nutrient-rich varieties like Mexican brown rice display reduced susceptibility to E. coli compared with Indian white rice, which showed the highest susceptibility. NP fortification demonstrated significant antimicrobial efficacy, particularly with ZnO and MgO NPs, which were more effective than their ionic counterparts in inhibiting bacterial growth. Results showed that ZnO and MgO nanoparticle treatments reduced E. coli growth by 72% and 68%, respectively, compared to untreated controls. Mexico brown rice treated with MgO NPs exhibited the lowest OD600 (0.01), indicating significantly enhanced resistance to bacterial proliferation.This research underscores the potential of nano-fortification not only to improve pathogen resilience in rice but also to maintain its nutritional integrity. This study provides a foundational framework for enhancing food safety against bioterrorism agents and supports the development of resilient agricultural practices.

Key words:  , rice, ZnO, MgO, post-harvest, food safety