The present study was carried out to evaluate the antimicrobial and antioxidant effects of black tea extract (BTE), green tea extract (GTE) and carob extract (CRE) in buffalo butter during storage at 4±1ºC for 12 weeks and compare to synthetic phenolic compound butylated hydroxytoluene, (BHT). The antibacterial effect and minimal inhibitory concentration (MIC) of extract against Listeria monocytogenes were studied. The effectiveness of these extracts (0.025 -0.05%) in butter made from pasteurized cream were evaluated by incubating (10 5 cfu/g) of Listeria monocytogenes. The GTE had completely inhibited (P≤0.05) the viability growth of Listeria monocytogenes during storage at 4±1ºC (10 -12 weeks) . During storage of butter made from unpasteurized cream, the population of lipolytic bacteria and mould&yeast markedly reduced (P≤0.05) by addition GTE (0.025 -0.05%) compared to other treatments. Also, BHT (0.025%) and GTE had similar inhibitory effect on Staph. aureus. E. coli and total counts. The BTE and GTE had a most antioxidant effect on decreasing the acid value (AV), peroxide value (PV) and thiobarbituric acid value (TBA). While CRE had less effect. Organoleptically, butter with added BTE, GTE and CRE gained the highest acceptance until 8 weeks compared with BHT treatment and control sample. This research has demonstrated that the use of BTE and GTE as a natural antimicrobial and antioxidant is a promising means to provide additional safety and improve the quality of buffalo butter during storage.

Fluoridated buffalo's and cow's skim milk with different concentration of sodium fluoride NaF (5 -20 p.p.m. F َ) and their effect on the characteristics of casein micelles, proteolytic digestibility and microbiological properties were investigated. Added NaF reduced the weight and size of casein micelles and this effect increased by increasing the concentration of NaF. After cold storage (5ºC±1/48 hrs) the reduction of weight and size of casein micelles of cow's skim milk contained 20 p.p.m. F َ was markedly higher than that of buffaloe's skim milk. Increasing the concentration of NaF significantly caused increase (P ≤0.05) in the rate of proteolytic digestion of buffalo's milk samples by trypsin and commercial (Alphintern®) enzymes compared with cow's ones. Growth of lactic acid cultures and pathogenic bacteria in buffalo's and cow's skim milk did was not affected by fluoride supplementation.

The effect of added sodium fluoride (NaF, 5-20 ppm. F َ) on some physico-chemical properties of buffalo's and cow's skim milk was investigated. Adding NaF (5-20 p.p.m. F َ) had no significant effect (P≥0.05) on the pH. The level of soluble calcium and the electrical conductivity (EC) were significantly decreased (P≤0.05) by adding NaF to buffalo's skim milk, but apposite trend was observed with cow's skim milk. Added NaF increased the ionic fluoride, and this effect increased with increasing the concentration of NaF. The optical properties at 280 and 260 nm of both milks contained (5-20 p.p.m. F َ ) were higher than those of the control samples. Cow's skim milk containing 15-20 p.p.m. F َ was higher ethanol stability at 85-90% than that of buffalo's samples. Fluoridated buffalo's skim milk (10-20 p.p.m. F َ) was more stable towards 5 and 7.5 mmol/L Ca 2+ compared with the control, but the corresponding cow's treatments were not influenced. Also, all fluoridated milk samples were heat stable. The rennet clotting time, firmness and synersis of buffalo's skim milk were higher significantly (P≤0.05) with adding 20 p.p.m. F َ than those of cows.