Abstract: [Objective] To verify whether the Sandwich ELISA technique can become an accurate detection method for the content of Bovin lactoferrin in various dairy products,including flavored fermented milk.[Method] Using optimized sandwich ELISA detection reagent to detect the content of Bovin lactoferrin in standard solutions,pasteurized milk samples,spiked pasteurized milk samples,12 common flavored fermented milks in the Beijing market,7 spiked flavored fermented milks,and 7 flavored fermented milks mixed with pasteurized milk,calculating the recovery rate and CV value. Using this detection reagent to test the sensitivity of milk lactoferrin to 72 ℃ heat treatment in 3 spiked flavored fermented milks;and comparing the detection of raw milk and pasteurized milk with the national standard detection method for milk lactoferrin.[Result] The detection reagent can detect milk lactoferrin in standard solutions and pasteurized milk samples,with a recovery rate 91.7%~106.4%.It was found that the content of milk lactoferrin in 12 flavored fermented milks was none;the recovery rate of 7 spiked flavored fermented milks was between 86.3%~109.1%,and the CV values were all far below 12%;the ratio of milk lactoferrin content in 7 flavored fermented milks mixed with pasteurized milk compared to the control group was between 92.3%~110.5%,and most CV values were far below 12%;the content of milk lactoferrin in 3 spiked flavored fermented milks decreased with the extension of heat time at 72 ℃,and the decline curves were similar. Through comparative analysis with the national standard method,the compliance rates of milk lactoferrin content detected by the ELISA method in raw milk and pasteurized milk were 97.54% and 111.2%，respectively，indicating that the accuracy of this detection method meets national standards.[Conclusion] The optimized sandwich ELISA detection reagent can accurately determine the content of milk lactoferrin in flavored fermented milk.

Key words: bovine lactoferrin, flavored fermented milk, Sandwich ELISA