الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
Biogenic amines are low molecular weight organic bases that possess biological activity. They can be formed and degraded as a result of normal metabolic activity in animals, plants and microorganisms. They are usually produced by the decarboxylation of amino acids.
After fish, cheese is the next most commonly implicated food item associated with histamine poisoning. Usually, cheese do not contain amines, but sometimes very high levels are found. During ripening cheese undergoes marked changes in body smoothness and flavor. These changes are associated largely with proteolysis, resulting in an increase in free amine acid content. Some of these amino acids can undergo further breakdown by specific bacterial decarboxylases to form carbon dioxide and amine.
During Domiati cheese processing the milk is subjected to heat treatment to give the desirable conditions for rennet enzymes activities. Many studies indicated that Damietta cheese may contain appreciable amounts of biogenic amines. It was reported that heat treatment had little effect on the content of biogenic amines in foods. Therefore, processed cheese may contain biogenic amines, Unfortunately, there is no limits concern the allowed level of biogenic amines in Damietta cheese mentioned in the Egyptian standard specification and the FAO/WHO for the above –mentioned reasons, the present study was aimed to :
Study the gross chemical composition of Damietta cheese as affected by storage at room temperature for different periods of time.
Study the chemical quality ( proteolysis and lipolysis ) of Damietta cheese as effected by storage at room temperature for different periods of time.
Study the microbiological quality of Damietta cheese as affected by storage at room temperature for different periods of time.
Determine the biogenic amines content in Damietta cheese as affected by storage at room temperature for different periods of time.
Finally, the relationship between biogenic amines of Damietta cheese as affected by storage at room temperature for different periods of time and different studied factors ( chemical compositions, lipolysis, proteolysis and microbiological quality) will be in the scope of this study.
Therefore, fresh Damietta cheese samples were processed in the laboratory of Dairy science department. Faculty of Agriculture, Mansoura University and packaged in tin containers immersed in whey. All of these samples were stored in room temperature for different periods of times i.e. 0, 3,6,9,12, 15,18,21,24 month’s. At the end of each period of time storage three containers were opened, cheese homogenized, and analyzed immediately. The average values are given +-SD.