Abstract: In order to study the effect of high pressure on amounts of microbes in cloudy pear juice,the cloudy pear juice was treated by 200～600 MPa pressure combined with heating,and amounts of microbes in the cloudy pear juice stored for 35 d at 4 ℃,22 ℃ and 37 ℃ respectively after being treated by 320 MPa pressure combined with 50 ℃ heating were assayed. Results showed that yeast and mold are not found in the juice treated by 300 MPa pressure,and bacteria are not found as pressure increasing to 400 MPa. Microbes are not found in the juice treated by 400 MPa or 600 MPa pressure combined with 50 ℃ heating. The treatment of 320 MPa pressure(keeping for 10 minutes) combined with 50 ℃ heating can kill or inactivate all the microbes in cloudy pear juice,and their amounts keep stable during the whole storage period. Storage conditions do not obviously affect amounts of microbes in cloudy pear juice treated by ultra-high pressure.

Key words: cloudy pear juice, ultra-high pressure combined with heating, microbes