Abstract: 【Objective】To study the detective method of Alicyclobacillus acidoterrestris in apple juice concentrate (AJC) by quantitatively competitive polymerase chain reaction (QC-PCR) system. 【Method】 The QC-PCR system for detection of Alicyclobacillus acidoterrestris was established through the primer design, PCR amplification, and reclaim of gel purification reagent box to construct and obtain the competitive template which was used as quantitative internal standards. 【Result】 The QC-PCR system was optimized and established in this study, and the detective sensitivity of the target template had gotten better from 5×104 to 50 molecules /PCR system. As a result of this, 5×102 target template molecules /PCR system was detected when the two templates co-amplified, and 5×103 cfu / PCR system of Alicyclobacillus acidoterrestris in AJC was detected. The detective time (4 h to 5 h) is remarkably shortened from traditional method（4 d or 5 d）using plate culture counting. 【Conclusion】 The method in this study is better than others in efficiency and specificity, which can be a reference for competitive template construction of microbe PCR and constructive methodology of QC-PCR. It has potential to be applied in AJC commercial production process for the rapid detection of Alicyclobacillus acidoterrestris.

Key words: Alicyclobacillus acidoterrestris, apple juice concentrated（AJC）, quantitative competitive Polymerase chain reaction (QC-PCR)