酸奶在发酵过程中会产生苯及苯的同系物，但是对于其产生规律和产生量一直缺乏研究。通过对比保加利亚乳杆菌和嗜热链球菌单独发酵和双菌种混合发酵，对酸奶中苯系物的产生规律和含量进行了研究，结果发现嗜热链球菌单菌种发酵比保加利亚乳杆菌单菌种发酵时苯系物的产生含量较高，苯系物产生最大值为后熟大约24 h左右，苯系物中苯乙酮最高，分别可以达到2.64±0.34 μg/L和1.95±0.22 μg/L。当使用两种菌种混合发酵时，苯及苯系物的产量高于单菌种发酵，通过比较不同配比的两种菌种的发酵结果发现嗜热链球菌:保加利亚乳杆菌=1:1时，苯系物产生量较低，其中产生量最高的甲苯为3.68±0.15 μg/L。参考饮用水的限量标准，不论是单菌种发酵还是混合发酵，酸奶中苯及苯系物的含量均低于饮用水的限量标准，因此酸奶中的苯及苯系物理论上不会对人体健康造成影响。

During fermentation, benzene and benzene derivatives can be produced in yogurt, but there is a lack of studies on the pattern of production and the amount produced. In this study, single-strain fermentation and mixed-strain fermentation using Lactobacillus bulgaricus and Streptococcus thermophilus were compared, and the pattern of production of benzene compounds and their contents in yogurt were studied. The results showed that the amount of benzene compounds produced in the single-strain fermentation with Streptococcus thermophilus was higher than that produced in the single-strain fermentation with Lactobacillus bulgaricus; the peak production of benzene compounds occurred after about 24 h of ripening, and acetophenone showed the highest content (Streptococcus thermophilus: 2.64±0.34 μg/L; Lactobacillus bulgaricus: 1.95±0.22 μg/L) among all the benzene compounds. When mixed-strain fermentation was performed with both strains, the contents of benzene and benzene derivatives in yogurt were higher than those of the single-strain fermentations. The results of mixed-strain fermentations with different ratios of the two strains were compared. The relatively lowcontents of benzene and benzene derivatives in yogurt were presented with a 1:1 ratio of Lactobacillus bulgaricus and Streptococcus thermophilus, and the content of methylbenzene was the highest amongst produced benzene compounds at 3.68±0.15 μg/L. According to the requirements for drinking water, the contents of benzene and benzene derivatives in yogurt for both single-strain and mixed-strain fermentation were lower than the maximum levels allowed for drinking water; hence, the benzene and benzene derivatives in yogurt, in theory, will not have an impact on human health.

国家“863”计划项目（2012AA101604）