The genus Alicyclobacillus includes Gram-positive, Gram-negative or Gram-variable, acidothermophilic, endospore-forming bacteria, which have been isolated from various environments, mostly acidic and geothermal soils, hot springs, fruit surface and spoiled fruit juices. The members of the Alicyclobacillus genus are characterized by the presence of ω-alicyclic fatty acids (ω-cyclohexane or ω-cycloheptane), the iso and anteiso branched-chain fatty acids, and the hopanoids as the major membrane lipids. There are 23 known species and 2 subspecies, with Alicyclobacillus acidoterrestris as the most significant. Certain species cause food spoilage in the fruit- and-vegetable juices industry. The spores of Alicyclobacillus are highly tolerant to high temperatures and low pH-values of fruit juices. What is more, they are naturally present on fruit surface and can readily enter the production environment of the fruit and vegetable processing. Due to high thermophilicity of these bacteria, the typical juice pasteurization conditions can stimulate spore germination. This is the reason why they can proliferate in juice and ipso facto cause fruit products spoilage. The family of Alicyclobacillaceae has continuously been modified and each successive year brings new species. Additionally, A. acidoterrestris is recognized as bacterium with a high evolution rate due to its rapid adaptation to changing environmental conditions.
1. Introduction. 2. Taxonomic identification of Alicyclobacillus and its systematic position. 3. The characteristic components of cell membranes and their functions. 4. Morphological and physiological characteristics. 5. Detection of Alicyclobacillus bacteria, 6. Summary
