传统发酵食品中乳酸菌的安全性评估

本文以传统发酵食品中分离的38株乳酸菌(lactic acid bacteria,LAB)为研究对象,利用溶血试验、明胶液化试验和吲哚试验测试受试菌株相关产毒代谢产物,采用K-B纸片法检测菌株对25种抗生素的耐药表型,运用聚合酶链式反应检测菌株携带的耐药基因。结果表明:38株乳酸菌的溶血试验、明胶液化试验和吲哚试验均为阴性,说明菌株在生长代谢过程中不产生相关毒力物质;38株菌对头孢曲松、头孢噻肟、四环素、多西环素、氯霉素、克林霉素和红霉素表现敏感;对其余18种抗生素呈不同程度耐受,其中对磺胺异噁唑耐药率最高(52.63%),其次是卡那霉素(34.21%)、万古霉素(31.58%)、阿米卡星(26.32%)、链霉素(15.79%)、利福平(2.63%);耐药谱分析受试大部分乳酸菌存在多重耐药现象;PCR共检测出3种耐药基因,分别是氯霉素耐药基因cat A(2.63%)、万古霉素耐药基因van A(5.26%)、利福平耐药基因rpo B(42.11%)。结果表明从传统发酵食品中分离的38株乳酸菌不存在相关产毒代谢产物安全隐患,但对部分抗生素呈现出不同程度耐受,并且利福平耐药基因rpo B的检出率较高。本研究为传统发酵食品中乳酸菌安全评价体系的完善提供理论参考。

Evaluation for Lactic Acid Bacteria Safety in Traditional Fermented Food

The 38 lactic acid bacteria (LAB) isolated from traditional fermented foods were used as the research object. The hemolysis test, gelatin liquefaction test, and indole test were used to test the toxin-producing metabolites of the tested strains. The K-B method was used to detect the sensitivity of strains to 25 kinds of antibiotics, and polymerase chain reaction was used to detect the drug resistance genes carried by the strains. The results showed that the hemolysis test, gelatin liquefaction test and indole test of 38 strains of lactic acid bacteria were all negative, indicating that the strains did not produce related toxic substances in the process of growth and metabolism. Thirty-eight strains of lactic acid bacteria were all sensitive to 7 antibiotics including ceftriaxone, cefotaxime, tetracycline, doxycycline, chloramphenicol, clindamycin, erythromycin; some strains were resistant to the other 18 antibiotics to varying degrees, with the highest resistance rate to sulfisoxazole (52.63%), followed by kanamycin (34.21%), vancomycin (31.58%), amikacin (26.32%), streptomycin (15.79%), rifampicin (2.63%). The drug resistance spectrum analysis showed that the tested Lactobacillus plantarum had multiple resistance phenomenon. PCR detected 3 kinds of resistance genes, namely chloramphenicol resistance gene catA (2.63%), vancomycin resistance gene vanA (5.26%), rifampicin resistance gene rpoB (42.11%). The results showed that 38 strains of lactic acid bacteria isolated from traditional fermented foods had no safety risks related to toxin-producing metabolites, but they were resistant to some antibiotics, and the detection rate of rpoB was high. This study provides a theoretical reference for the improvement of lactic acid bacteria safety in traditional fermented food.