Analysis of Alicyclobacillus acidoterrestris Spores from Different Sporulation Media Subjected to Wet-Heat

The presence of Alicyclobacillus acidoterrestris endospores in fruit juices is a significant problem for the juice industry since they are able to survive pasteurization subsequently leading to the spoilage. To evaluate the mechanism of wet-heat, structural damage and the leakages of intracellular materials of A. acidoterrestris DSM 3922 spores from different sporulation media was studied at 90 °C (15–45 min). For sporulation, Bacillus acidoterrestris agar, Bacillus acidocaldarius agar, potato dextrose agar and malt extract agar were used. Based on the scanning electron microscopy, loss of internal volume and structural integrity were observed following heating which were further confirmed by the leakages of intracellular components. The obtained results suggest that the inactivation of A. acidoterrestris DSM 3922 spores by wet-heat is associated with damage to the coat and inner membrane depending on the sporulation medium composition and heating time.