Effects of temperature, pH and sodium chloride on antimicrobial activity of magnesium oxide nanoparticles against E. coli O157:H7

Abstract

Aim This study was done to determine the effects of temperature, pH and sodium chloride (NaCl) on antimicrobial activity of magnesium oxide (MgO) nanoparticles (NPs) against E. coli O157:H7. Methods and results Culture conditions were established by varying the pH (5.0, 7.2 and 9.0), NaCl concentration (0.5, 2.0, 3.5 and 5.0%, w/v), and incubation temperatures (4, 12, 22 and 37°C). At each condition, the antimicrobial activities of MgO‐NPs (0, 1, 2 and 4 mg/ml) against E. coli O157:H7 were measured. Four‐way analysis of variance indicated interactions among all factors had a significant effect (p ≤ 0.05) on the antimicrobial activity of MgO‐NPs. The concentration of MgO‐NPs necessary to cause a 5‐log reduction of E. coli O157:H7 under the most inhibitory conditions (37°C, pH 9.0, and 5.0% NaCl) was 0.50 mg/ml of MgO‐NPs. Conclusion The antimicrobial activity of the MgO‐NPs increased significantly (p ≤ 0.05) with increased temperature, pH and NaCl concentration in TSB. Significance and impact of the study The influence of intrinsic and extrinsic factors on antimicrobial activity of MgO‐NPs we found will contribute to the development of microbial decontamination strategies using MgO in the food industry.

Biogenic Synthesis of Photosensitive Magnesium Oxide Nanoparticles Using Citron Waste Peel Extract and Evaluation of Their Antibacterial and Anticarcinogenic Potential

“…From the results presented in Table 2 and Figure 5 , it is apparent that superior antibacterial potential of CP-MgONPs increases with concentration. Similar results were recently reported by Yoon et al who established that increasing the dosage of formed MgONPs improved their antibacterial activity towards E. coli [ 70 ]. Das et al also demonstrated the dose-dependent effectiveness of MgONPs towards the different strains of pathogens [ 71 ].…”