浓缩苹果汁中嗜酸耐热菌的分离及检测条件探讨

目的　对浓缩苹果汁中嗜酸耐热菌进行分离培养,研究其生理特性和最佳检测方法。方法　采用L16 (45)正交试验,对培养基种类、pH值、热休克方式、果汁稀释度四个影响浓缩苹果汁中嗜酸耐热菌检测的因素进行了研究,以菌落数多少进行综合评分,优选最佳检测方法。结果　分离出的嗜酸耐热菌不是单一的一种菌,而表现为多形态。检测该菌的最佳方法:70°Brix浓缩苹果汁样品经10 倍稀释,80 ℃热处理10 min,室温水自然冷却至50 ℃,接种于pH值为3.5的k琼脂培养基,置45℃培养3 d。结论　该方法可较大程度地提高苹果汁中嗜酸耐热菌检测的灵敏度。

Study on isolation and detection of thermo-acidophilic bacteria in apple juice concentrate

Objective To determine the best method to detect thermo-acidophilic bacteria in apple juice concentrate. Methods L 16 (4 5) orthogonal test was applied to analyse the four factors, including culture medium, ways of heat shock, dilution degrees of AJC and pH value. The results were comprehensively scored according to the number of colonies. Results The isolated bacteria were polymorphous. A better method was as follows: after being diluted to 1∶10, the AJC was submitted to a heat shock at 80 ℃ for 10 min, and then spread on k agar with a pH value of 3.5. Samples were incubated at 45 ℃ for 3 days, and then enumerated. Conclusion This method can considerably improve the sensitivity of detecting thermo-acidophilic bacteria in apple juice concentrate.