临期盒装豆腐腐败菌鉴定及抑菌效果评价

Identification of spoilage bacteria in deadline boxed tofu and evaluation of their inhibitory

【目的】探究临期盒装豆腐优势腐败菌及对其抑制效果,延长盒装豆腐货架期。【方法】以临期盒装老豆腐和内酯豆腐为研究对象,分离优势腐败菌,并通过16S rDNA全序列分析法对腐败菌进行鉴定。分别添加不同质量浓度的山梨酸钾、脱氢乙酸钠、乳酸链球菌素单一组及3种防腐剂的复配组到样品中,采用加速试验,以抑菌率为指标,通过响应面法确定最佳复配防腐剂配方和质量浓度。【结果】临期盒装豆腐中的优势腐败菌为植生拉乌尔菌(Raoultella planticola)和沃纳利葡萄球菌(Staphylococcus warneri)。单一防腐剂的抑菌率随质量浓度的增加而增加,而复配防腐剂的抑菌效果更好。当山梨酸钾为0.21 g·L^(-1)、脱氢乙酸钠为0.15 g·L^(-1)、乳酸链球菌素为0.17 g·L^(-1)时,对植生拉乌尔菌的抑菌率最高,为25.48%;当山梨酸钾为0.36 g·L^(-1)、脱氢乙酸钠为0.11 g·L^(-1)、乳酸链球菌素为0.10 g·L^(-1)时,对沃纳利葡萄球菌的抑菌率最高,为32.07%;当山梨酸钾为0.29 g·L^(-1)、脱氢乙酸钠为0.03 g·L^(-1)、乳酸链球菌素为0.01 g·L^(-1)时,该复配防腐剂对2种腐败菌均有较好的抑菌效果,抑菌率分别为25.17%和32.42%;将该复配防腐剂添加到回接腐败菌的盒装豆腐中,并于37℃下进行储藏,处理后的盒装豆腐货架期相应延长2 d,经测算相当于在0~4℃下货架期延长7 d。【结论】在加速试验条件下,复配防腐剂可以有效抑制临期盒装豆腐中优势腐败菌,延长货架期。

【Objective】In order to explore the dominant spoilage bacteria and inhibitory effect of nearexpired boxed tofu,and extend its shelf life in the market.【Method】Using the near-expired boxed tofu and lactone bean curd as study objects,the dominant spoilage bacteria were isolated,and the spoilage bacteria was identified by 16S rDNA sequencing analysis.Adding with different concentrations of Potassium sorbate,Sodium dehydroacetate,Nisin single group,and three composite groups of preservatives to the sample,the optimal composite preservative formula and concentration was determined by response surface methodology with antibacterial rate as an indicator under the accelerated test.【Result】The results showed that the dominant spoilage bacteria in near-expired boxed tofu in Zhengzhou City were Raoultella planticola and Staphylococcus warneri.The inhibitory rate of a single preservative increased with its concentration,while the antibacterial effect of compound preservative was better.When potassium sorbate was at 0.21 g·L^(-1),sodium dehydroacetate was at 0.15 g·L^(-1),and Nisin was at 0.17 g·L^(-1) in combination,the inhibitory rate on Raoultella planticola was the highest at 25.48%;When potassium sorbate was at 0.36 g·L^(-1),sodium dehydroacetate was at 0.11 g·L^(-1),and Nisin was at 0.10 g·L^(-1) in combination,the inhibitory rate on Staphylococcus warneri was the highest at 32.07%;When potassium sorbate was at 0.29 g·L^(-1),sodium dehydroacetate was at 0.03 g·L^(-1),and Nisin was at 0.01 g·L^(-1) in combination,the inhibitory rates on the two spoilage bacteria were the highest,at 25.17%and 32.44%,respectively.When the compound preservative was added to the boxed tofu with spoilage bacteria and stored at 37℃,the shelf life was extended by 2 days,which was estimated to be equivalent to extending the shelf life for 7 days at 0-4℃.【Conclusion】The results of this study under the accelerated test conditions indicate that the combination of preservatives can effectively inhibit the dominant spoilage bacteria in temporary boxed tofu,and extend the shelf life.