Alicyclobacillus acidoterrestris is a thermo-acidophilic, sporeforming bacterium commonly associated with spoilage incidents in fruit juice and fruit based beverages. The spores produced by this microorganism are capable of survival through traditional commercial pasteurisation processes normally applied to fruit juice, drinks, purees and concentrates. Upon germination and outgrowth, strains may produce tainting compounds, notably guaiacol and halophenols, producing a disinfectant-like off-odour.
The aim of this study was to assess the genetic diversity of A. acidoterrestris using random amplification of polymorphic DNA-PCR (RAPD-PCR). RAPD-PCR was utilised to investigate the diversity of isolates from geographically distinct regions and product origins. A total of 220 isolates of Alicyclobacillus spp. which were recovered between 1997 and 2016 from a range of fruit-containing-products produced in Australia, New Zealand, China, Brazil and Mexico were assessed. Two referencing primers BA-10 and F-64 were used to generate profiles of random fragment amplifications.
Based on banding patterns the 220 isolates of Alicyclobacillus spp. and A. acidoterrestris were grouped into 25 unique clusters. Distinct patterns were observed across product origins and geographical regions.
The results of this study improve the understanding of the genetic diversity of A. acidoterrestris from a range of geographical and product origins. These results will be further validated and used in the selection of a representative group of Alicyclobacillus spp. isolates for further studies on guaiacol production and whole genome sequencing. This increased understanding is intended to provide broad and valuable outcomes to aid the management of off-odour development caused by A.acidoterrestris in shelf-stable fruit juice and fruit based products.