الفهرس 
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Abstract
Antimicrobial food packaging is an innovative way to inhibit microbial development and extend the shelf life of foods. Along with attempts to reduce foodborne pathogens and extend the shelf life of foods, the world has become more concerned about decreasing plastic wastes to safeguard the ecosystem.
Therefore, the current study aimed to development of starch-based eco-friendly, biodegradable antimicrobial films (BAFs) incorporated with Origanum majorana ethanolic extracts, nano-emulsion, and chemically synthesized (C-AgNPs) and biosynthesized silver nanoparticles (B-AgNPs) to combat foodborne pathogens and prolong the shelf life of both beef and chicken meat.
Initially, the antimicrobial activity of these antimicrobials was evaluated in-vitro through well diffusion assay against pathogenic E. coli and pathogenic coagulase positive S. aureus isolated from meat samples.
After that, these antimicrobials were incorporation in BAFs and their antimicrobial activity was investigated through the disc diffusion assays against pathogenic E. coli and pathogenic coagulase positive S. aureus.
Based on the in-vitro investigation and preliminary film synthesis experiments, only BAFs incorporated with B-AgNPs and C-AgNPs were selected for the challenge study, while others were abandoned due to either their poor antimicrobial activity or their poor physical and mechanical properties.
Beef and chicken meat slices were experimentally inoculated with a cocktail consisting of about 8 log10 CFU/mL of three pathogenic E. coli and S. aureus strains respectively, to obtain a concentration of about 6.6 log10 CFU/cm2 and wrapped with the home-made BAFs.
Subsequently, the remaining bacterial counts in wrapped beef slices were determined throughout the refrigerated storage (4 °C) for up to 14 days. The obtained results showed that at day 0 (4 h post-wrapping), BAFs with B-AgNPs (one mM), B-AgNPs (2 mM), C-AgNPs (one mM), and C-AgNPs (2 mM) reduced pathogenic E. coli cocktail by 1.57, 1.77, 1.63 and 1.82 log10 CFU/cm2, respectively.
Eventually, at day 14 the log reductions were 4.49, 4.99, 4.6, and 5.04 log10 CFU/cm2, respectively when compared with un-wrapped samples. Moreover, they were 4.21, 4.71, 4.32 and 4.76 log10 CFU/cm2, respectively when compared with control films wrapped samples.
On the other hand, the chicken breast fillet slices were determined throughout the refrigerated storage (4 °C) for up to 10 days. The obtained results showed that at day 0 (4 h post-wrapping), BAFs with B-AgNPs (1 mM), B-AgNPs (2 mM), C-AgNPs (one mM), and C-AgNPs (2 mM) reduced pathogenic S. aureus cocktail by 1.58, 1.77, 1.65 and 1.87 log10 CFU/cm2, respectively.
Although, at day 10 the log reductions were 4.76, 5.34, 4.89, and 5.53 log10 CFU/cm2, respectively when compared with un-wrapped samples while, they were 4.66, 5.24, 4.79, and 5.43 log10 CFU/cm2, respectively when compared with control films wrapped samples.
Additionally, based on the sensory evaluation of un-inoculated wrapped chicken breast fillets, BAFs extended the shelf-life of both samples by about 4 days as compared with control samples, while the BCF extend their shelf-life by about 2 days.
from this study, it could be shown that chemically and biosynthesized silver nanoparticles had strong antimicrobial effect against both gram negative and gram positive bacteria even when they incorporated in homemade biodegradable films, so they could be used in meat packaging to save our environment and increase the safety and shelf-life of meat.