Effect of culture conditions and fruit juice on the growth characteristics of Alicyclobacillus

It is known that Alicyclobacillus are one of the most important bacteria causing pasteurized fruit juice spoilage. However, there have no unified culture methods for Alicyclobacillus,and their pollution characteristics have not clear. In this paper,the effect of pH,seven kinds of common culture medium and nine kinds of fruit juice on the growth of Alicyclobacillus were investigated. Meanwhile,the metabolites of Alicyclobacillus inoculated in nine kinds of fruit juice were detected using solid phase microextraction(SPME)and gas chromatography-mass spectrometry(GC-MS). As the result showed,Alicyclobacillus grew best under condition pH4.0,poorer in pH2.5 and didn't grow in pH6.0~7.0. Compared with other five kinds of medium(YSG,K,SK,PDB and Nutrient Broth),AAM and BAT were more suitable for cultivation of Alicyclobacillus. Alicyclobacillus were inoculated in nine kinds of fruit juice and the growth of bacteria difference was significantly. The bacteria grew best in grape juice and followed in orange juice with 1.5×10⁴ CFU/mL and 8.5×10³ CFU/mL of bacteria counts respectively. Alicyclobacillus grew very slowly in pineapple juice and grapefruit juice with 4.4×10² CFU/mL and 1.9×10² CFU/mL of bacteria counts respectively. In addition,no 2,6-dibromophenol was detected in all fruit juices which were inoculated Alicyclobacillus. 8.6~23.9 μg/L of guaiacol was detected in these eight kinds of fruit juice,except for grape juice.