الفهرس 
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Abstract
Chitosan/silver nanoparticles not only have the antibacterial affects, but also have good safe guarantee in human edible and touchable fields. Its antibacterial activity, safety and nontoxic, odorless. This study aimed to design silver nanoparticles incorporated into chitosan with biopolymer to form thin films and used as antibacterial activity on hard cheese to increasing the shelf life. This thesis comprised four chapters. In the first chapter: included the introduction about the importance of the controlling microorganisms and types of bacteria in dairy product that is the one of the most serious problems in our dairy industrial , for example from bacteria , such as Escherichia coli, , Staphylococcus aureus Bacillis subtilis, Salmonella typhi ,Candida albicans Aspergillus fumigatus .…...etc. The pathogenic microorganisms such as bacteria, fungi and yeast from human and animal waste that are found in contaminated raw milk. These types of pathogenic microorganisms can display a range of toxic effects in humans from immune suppression to acute poisoning. Generally, cheese spoilage is one of the main problem facing our Ras cheese production because cheese is crucial to the sustenance of customer food in Egypt, Therefore, very important prevent the bacteria growth on cheese surface and how to reduce these growth and get rid of the pathogenic microorganisms is one of the most important research fields. Widely used available biopolymers Nanomaterials also being used for antimicrobial mainly because they are a cheap resource or a freely available resource. Chitosan is the natural polysaccharide comprising copolymers of glucosamine and N-acetyl glucosamine and can be derived by the partial deacetylation of chitin. It is a biodegradable, biocompatible and hydrophilic polymer of low toxicity. It is a material found in abundance in shells of crustacean such as lobsters, prawns and crabs. It is insoluble under alkaline and neutral conditions, but can react with inorganics and organic acids such as hydrochloric acid, lactic acid, acetic acid and glutamic acid under acidic conditions. Chitosan is a well-known antimicrobial agent. The capability of chitosan used to against pathogenic microorganisms makes it a promising candidate for cheese preservatives .The process depends upon nanomaterial from chitosan or silver breaking cell wall to microbial. the present study involved the preparation of silver, chitosan and silver nanoparticles incorporated into chitosan and carried on specific polymer. The advantages of this process are no need to have extra preserve agents as well as the process can be conducted on direct product. The developed silver nanoparticles by this process have excellent antibacterial properties. Finally, chitosan/silver nanocomposite could be used as antibacterial in industrial food. Also this chapter contains a literature thermal and mechanical properties material silver nanoparticles with thin film, chitosan nanoparticles carried on specific polymer, chitosan and silver nanoparticles incorporated into chitosan and carried on specific polymer coating cheese, the antibacterial activity in the last 10 years. The second chapter: contains the experimental procedures such as materials, instrumentation and the methods used in this research. The third chapter: contains the results and discussion of silver nanoparticles incorporated into chitosan with biopolymer to form thin films and study of the spectroscopic characterization and used as antibacterial activity on hard cheese to increasing the shelf life. The last chapter: contains the references which have been utilized in this study.