Bacterial Characteristics And Control Methods Of Alicyclobacillus Acidoterrestris In Apple Juice

Alicyclobacillus acidoterrestris is commonly known as acidphilic and thermoresistant bacteria which becomes the main contaminated bacteria in apple juice. Alicyclobacillus acidoterrestris has become an important factor to affect apple juice quality, also limiting apple juice international market competitiveness. Although some success on Alicyclobacillus acidoterrestris controlling techniques in juice production have been made, we haven't resolved the problem radically and lacked practical control technique yet. So in-depth and extensive research on inhibiting Alicyclobacillus acidoterrestris growth have theoretical and practical impact on improving the technical level and product quality. In this paper, Alicyclobacillus acidoterrestris strains were isolated from Rotten Jinshua apples and identified by morphology, physiological and biochemical experiments, and 16S rDNA molecular analysis. The effects of temperature and pH on the growth and the heat resistance on their spores were also investigated. Effects of chemical and biological methods on strains growth were also taken into considerations as well. The main results and conclusions were as follows:1. The isolation and identification of Alicyclobacillus acidoterrestris from Rotten Jinshua apples:Two isolated strains and standard bacteria CICC 10374 which were verified by morphological physiological and biochemical characteristics had obvious similarity. The homology of two isolated strains and standard bacteria CICC 10374 reached to 99% by 16S rDNA molecular analysis and phylogenetic tree analysis. Eventually A-1 and A-2 were identified as Alicyclobacillus acidoterrestris.2. Bacterial characteristics of Alicyclobacillus acidoterrestris:A-1 and standard bacteria roughly had the same growth trend. A-1 and standard bacteria tured the delayed phase into the logarithmic phase at 4h and tured into stationary phase at 8h. After 16 hours, Bacteria turbidity of A-1 and standard bacteriais was slow down. However, A-2 grew faster. Bacteria turbidity became slowly down at 14h. A-1, A-2 could grow in a relatively wide range of temperature. Optimum growth temperatures of A-1 and A-2 was 45 ?. Growth of pH was in the range of 2.5-6.5. The optimal pH values for A-1 and A-2 were 4.0 and 3.5, respectively.3. Heat resistance results of Alicyclobacillus acidoterrestris:Minimum D-value of A-1 spores as a function of 90?, pH 3.5 and 5°Brix was 10.31min. Minimum D-value of A-2 spores as a function of 95 ?, pH 3.5 and 12.5°Brix.was 14.39min.4. Control the growth of strain A-2:Inhibitory effect of 1 and Sodium benzoate on strain A-2 was obvious. Inhibitory effect of 3 mg/kg 1 showed the significant difference at the different time. At 4 mg/kg 1 with 120h could be achieved to limited requirement of Alicyclobacillus acidoterrestris in the apple juice concentrate trade. Inhibitory effect of 200 mg/kg Sodium benzoate showed the significant difference at the different time. At 200mg/kg with Sodium benzoate 120h could be achieved to limited requirement of Alicyclobacillus acidoterrestris in the apple juice concentrate trade.