分光光度计法快速检测果汁中嗜热耐酸菌

酸土脂环酸芽孢杆菌(Alicyclobacillus acidoterrestris)是果汁污染的主要嗜酸耐热菌。它可以将香草酸或者香兰素转化为愈创木酚，后者在过氧化物酶的作用下产生红褐色产物，从而可以快速检测该菌。根据这个原理，设计实验探究该颜色反应的最优培养条件以及实际体系中检测该菌的可行性。结果表明：在静止培养情况下，在BAM培养基中添加100μg/kg的香草酸最有利于愈创木酚的产生；不同浓度的嗜热耐酸菌芽孢液在上述条件下培养，随着浓度的降低产生高浓度愈创木酚时间依次延迟，最低浓度为3个/mL的芽孢培养21h后，愈创木酚含量用分光光度计测定的光密度值OD470为1.0以上，为肉眼可见的红褐色；模拟实际体系下的培养也出现了颜色反应，证明该方法确实可以实现果汁中嗜热耐酸菌的快速、简便、高灵敏度的检测。

A Rapid Spectrometric Method for Detecting Alicyclobacillus acidoterrestris in Fruit Juice

In the presence of Alicyclobacillus acidoterrestris, vanillic acid and vanillin can be converted into guaiacol, which can be further converted into a reddish-brown product by peroxidase. Based on this color reaction, a method was developed to spectrometrically detect the presence of Alicyclobacillus acidoterrestris in real systems. In static culture, BAM medium with the addition of 100μg/kg vanillic acid was the most favorable for guaiacol formation. The peak value of guaiacol concentration was delayed along with the decrease of bacteria concentration. A visible color was formed in medium and its OD470 could reach up to 1.0 or even more after 21 hours of culture at the initial spore density of 3 spores/mL. And the same result also was obtained in an apple juice system. Thus, this method can allow rapid, simple and sensitive detection of Alicyclobacillus acidoterrestris in fruit juice.