الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Although milk and its products are valuable foods which are considered as conventional sources of good quality for proteins, essential fatty acids, phospholipide, minerals and vitamins, they may become harmful &.s they are subjected to contamination from various sources during their production and handling as they provide an ideal media for the growth of many pathogenic microorganisms among which, staphylococc i are the most prominent. Staph. aureus presents a potential public health hazard as it is a.n extremely common ca.use of food poison i~, skin infections and many serious systematic infections. Incidence of Staph. aureus in milk and dairy products 1s usually as a result of contaminat°ion from bovine udder or from human sources e..nd therefore milk ELnd its products can represent a real danger in spreading this disease and others because of the unhygienic conditions and poor sanitation on which milk is produced and handled. Staph aureus organisms produce six enterotoxin types, n&.llle1y A,B,O,D,E and F, all of these causing food poison ing. a The detection of these enterotoxins in food are time consuming. tedious and expensive therefore a rapid and inexpensive screening procedure for routine examin ation of food is needed, hence the trial of thermonuclease test in the present work which aimed at searching for Staph. aureus organisms in raw milk and other dairy products collected from different places in Alexandria; study the toxigenicity of the Staph. aureus str&.ins and to find out the relationship between the presence of Staph aureus and its products as tbermonuclease and enterotoxins in milk and some dairy products. A total of 580 samples of raw milk, Kareish cheese, Damietta cheese. hard cheese, butter, cream and ~abady, (J80,50,25,25,25,25 and 50 samples of each respectively) were collected from dairy farms 6.nd retailers in Alex. ’” city. B-P agar; (S.M.A~a.r; V.J. agar and Staph. 110. were used for isolation of Staph aureus, then the i80 la.ted stra.ins ident ified morphologically and biochemically, all the isolated strhins were tested for surcepti bllity &.gainst different ant ibiot ics and tested for enterotoxin product ion and phage typing test was done fOT. enterotoxigenic strains, a.lso the a.bove samples of milk C:l.nd dairy products were exa.mined for the presence of enterotoxin and thermonuclease. . It was found that: 1) Out of the 580 samples of examined milk and dairy products, 25.5 were positive for Staph. aureus with a. total of 148 isolated strains. Staph a.ureus was detected in 25.8 and 36.0 & 20.0 24.0 and 6.0 out of examined samples of raw milk, cheese and butter, Cream and Zabady respect ive1y. 2) Baird-parker agar gave better results then vogel Johnson aga.r than LSM agar and Staph. 110 agar in the isolation of Staph aureus. 3) Antibiotics of common use such as penicillin G, Anpici11in and co1imycin have lost the greatest part of their effect against Staph. aureus, while Genta.mycin, Neomycin and Kanamycin were the most active bntibiotics against Staph. aureus ~solated from milk bnd dairy products. 4) Out of 148 StEl.ph. El.ureus stra.ins tested for enterotoxins production including 98. 36, 5. 6 and 3 Staph.