In order to understand and control thermo-acidophilic bacteria in apple juice concentrate,a strain of thermo-acidophilic bacteria was screened,isolated,and purified from the apple juice concentrate in expansion bags.The thermo-acidophilic bacteria were identified by cell morphology,colony morphology,16S rDNA test with phylogenetic tree analysis.The result showed that the homology of isolated strain and standard bacteria ATCC 49025 reached to 99.51％.The isolated strain was identified as Aiyclobacillus acidoterrestris.The thermal stability and acid-base stability of the strain were examined by heat and acid-base treatment.Orthogonal experiment was carried out on the base of single factor experiments,and it was found that the optimal sterilization parameter was to heat treat at 105 ℃ for 20 min at pH 6.0.Under this parameter,the number of colonies growing on the plate was 0.The result indicated that the extraction conditions have good rationality and reliability.The conclusion provided a theoretical basis for the control of thermo-acidophilic bacteria in apple juice concentrate.
关键词
浓缩苹果汁/筛选分离/嗜酸耐热菌/分离鉴定/菌群特性
Key words
Apple juice concentrate/screening and isolation/thermo-acidophilic bacteria/separation and identification/microbial characteristics
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