Of the four known species of the genus Alicyclobacillus only Alicyclobacillus acidoterrestris is of significance for the beverage industry. Alicyclobacillus acidoterrrestris is a Gram-positive, obligately aerobic rod-shaped bacterium which is able to multiply event at pH 2.2. The heat resistance of the spores is extremly high (D95°C 1.0–14.5 min, z-value=6.4–11.3°C). Alicyclobacillus acidoterrestris can be detected using various methods, including flow cytometry, PCR, detection of fatty acids, ribotyping and cultural methods with biochemical identification. For routine analysis a cultural method is recommended because it is more reliable and simple.