EN
Alicyclobacillus spp. is an important thermoacidophilic, spore-forming spoilage bacterium that is a major concern for beverage and juice industries. This study was undertaken to: (i) estimate the incidence of Alicyclobacillus spp. and A. acidoterrestris in Polish apple and dark berry juice concentrates, and (ii) evaluate the ability of isolated A. acidoterrestris strains to spoilage of these juices after dilution to single strength. Polish apple and berry juice concentrates were screened for the presence of Alicyclobacillus spp. between 2002 and 2015. Incidence of Alicyclobacillus spp. in apple juice concentrates (n=1164) range from 27.3 to 86.8%, depending on the year. The species A. acidoterrestris accounted, depending on the year, from 12.7 to 100.0% of all isolated strains. Among the dark berry juice concentrates (n=146), approximately 60.0% were contaminated by Alicyclobacillus spp. Incidence of A. acidoterrestris strains in dark berry juice concentrates range from 4.2% in blackcurrant up to 40.0% in raspberry. Single strength apple juice promoted the growth of eight of the tested A. acidoterrestris strains (> 7 log cfu/ml) when was incubated at 45°C. No A. acidoterrestris growth was observed in single strength chokeberry, raspberry, strawberry, cherry and blackcurrant juices during 28 days incubation at 45ºC.