الفهرس 
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Abstract
The development and accumulation of biogenic amines in cheeses as affected by storage time and temperature was followed. The changes occurred in the chemical composition and ripening indices of the samples were also followed up and the microbiological aspects were recorded. The cheese types under study include: hard cheese (Ras and Kachkaval), semi hard cheese (Edam and Gouda) and soft cheese (Domiati cheese and ultrafiltrated white cheese). These types were stored under 27<U+F0B1>3<U+F0B0>C and 6<U+F0B1>1<U+F0B0>C for 12 months for hard cheese, 9 months for semi hard cheese and 24 weeks for soft cheese. In hard cheese, there were gradual decrease in both moisture content and pH values, and a gradual increase in salt content, T.N. and titratable acidity (T.A.). The rate of changes during storage period was more pronounced in the samples stored at 27<U+F0B1>3<U+F0B0>C than those stored at 6<U+F0B1>1<U+F0B0>C. Similar trend observed for hard cheese and semi hard cheese samples was observed. During storage of soft cheese samples, it was observed that moisture content, T.N. and pH values gradually decreased along with the storage period; whilst, its salt content and T.A. increased. All ripening indices (S.N., N.P.N., S.R.I.) increased by prolonging storage period. The rate of ripening occurred 27<U+F0B1>3<U+F0B0>C was higher than that occurred at 6<U+F0B1>1<U+F0B0>C. Values of ripening indices were changed according to the type of cheese. During storage period of hard cheese and semi hard cheese a gradual decrease was noticed for T.C.; proteolytic bacteria; coliform bacteria, enterococci and lactobacilli. The rate of decrease at 6<U+F0B1>1<U+F0B0>C was higher than that observed at 27<U+F0B1>3<U+F0B0>C. While in soft cheese samples both T.C. and lactobacilli increased during the first stages of storage, then decreased till the end of storage period. The counts of proteolytic bacteria, enterococci and E. coli decreased gradually till the end of storage period. The UF white cheese were free from E. coli due to heat treatment. The prevalent amine in Ras and Kachkaval cheeses was tryptamine. It reached to its maximum values 23.94 mg/kg and 22.00 mg/kg after 8 and 12 months of storage, respectively. Tyramine was the lowest detected amine in the two cheese types. Histamine contents increased in the first stages of storage, reached to its maximum value (4.84 mg/kg) after 8 months in Ras cheese and (4.77 mg/kg) at the end of storage period of Kachkaval cheese. <U+F062>phenylethylamine showed a gradual increase in the first stages of storage, then it decreased till the end of storage. The predominant amine in Edam cheese was tryptamine. It gradually increased along storage period and reached to 10.21 mg/kg after 9 months. Whilst, <U+F062>phenylethylamine was the predominant amine in Gouda cheese. Its maximum value was for 24.83 mg/kg after 6 months of storage. The lowest amine at both types of cheese was tyramine. Histamine gradually increased in Edam cheese reached to its maximum (2.99 mg/kg) at the end of storage period.In Gouda cheese it decreased at the end of storage period. That the prevalent amine was tryptamine whilst, the lowest amine was tyramine. Histamine and <U+F062>phenylethylamine values increased along with the storage period of traditional Domiati cheese, while in UF white cheese they were gradually increased at the first stages, then it decreased till the end of storage period.