Alicyclobacillus are motile gram positive rod-shaped bacteria which are common in soil and water. The bacteria are thermophilic and acidophilic, and can commonly be found on fruit at orchards, especially apples and oranges. Due to their high tolerance for heat – Alicyclobacillus endospores can resist tempe-ratures of 90 °C and higher – and low pH, Alicyclobacillus is a spoiler of fruit juices, as spores brought in with fruit survive and are activated during pasteurization. 

Currently 18 different species of Alicyclobacillus are described. A. acidoterrestris is the most important spoiler. Guajacol, which is one of the metabolites produced by Alicyclobacillus, is not harmful when consumed, but its detection threshold is so low that even small amounts cause product spoilage. Contaminated fruit juice has an unpleasant phenolic smell and taste. 

The detection of all Alicyclobacillus species in one single test provides a simple and easy “go-no go” screen for presence in your sample.