Improvement of antifungal and antibacterial activities of food packages using silver nanoparticles synthesized by iturin A

Contamination of food with food-borne bacteria and fungi presents significant hazards to food preservation and human health. Iturin A has attractive antifungal activity but low antibacterial activity, while silver nanoparticles (AgNPs) have significant antibacterial activities but present a potential hazard to human health. To overcome these limitations, iturin was used to synthesize AgNPs and form iturin-AgNPs, which were mono-dispersed and 20 nm in average size within the range of 10–30 nm. The formation of iturin-AgNPs involved the production of O₂^•− by the phenolic groups of iurin A under UV irradiation and in the presence of O₂. The antimicrobial activities of iturin-AgNPs and the AgNPs (average size 20 nm) stabilized by polyvinyl pyrrolidone (PVP-AgNPs) were evaluated against typical food borne bacteria and fungi in vitro. Iturin-AgNPs was also prepared as paper packages for the use in protection of oranges from fungal contamination alone and the use of prevention of chicken from bacterial contamination with the comparison of PVP-AgNPs. The iturin-AgNPs showed wider antimicrobial spectrum, a lower silver concentration, and higher antibacterial and antifungal activities than PVP-AgNPs. The study developed a new agent to protect foods from bacterial and fungal contamination during storage.