防腐剂对地衣芽孢杆菌的抑制效果

通过药敏纸片法、最小抑菌质量浓度(MIC)法测定地衣芽孢杆菌对不同防腐剂的敏感性,利用正交试验设计筛选出最佳的防腐剂组合,并对获得的最佳防腐剂组合的抑菌效果进行验证。结果表明:地衣芽孢杆菌对山梨酸钾、乳酸钠不敏感;对Nisin、ξ-聚赖氨酸和尼泊金乙酯较为敏感,在20mg/mL时其抑菌圈直径分别为9.25、10mm和7.5mm,MIC分别为0.078、0.078mg/mL和2.5mg/mL。正交试验结果表明:当Nisin、ξ-聚赖氨酸和尼泊金乙酯质量浓度分别为0.313、0.313mg/mL和0.125mg/mL时,对地衣芽孢杆菌的抑制效果最佳,可使基质中的地衣芽孢杆菌数(空白样品中为5.48(lg(CFU/g))降低2(lg(CFU/mL))。选择这一最佳组合分别对其在肉制品、乳制品、果汁中的应用效果进行测定,结果显示在0～4℃条件下,复配防腐剂的效果较好。

Inhibitory Effects of Different Preservatives on Bacillus licheniformis

The sensitivity of Bacillus licheniformis to different preservatives was tested by disk diffusion method and minimum inhibitory concentration(MIC) assay.The optimal combination of preservatives against Bacillus licheniformis was determined using orthogonal array design method and validated.The results showed that Bacillus licheniformis was not sensitive to natamycin,sorbic acid,potassium and sodium lactate,but sensitive to nisin,ε-polylysine and ethylparaben,revealing an inhibition zone diameter of 9.25,10 mm and 7.25 mm and an MIC of 0.078,0.078 mg/mL and 2.5 mg/mL,respectively.The combination of nisin,ε-polylysine and ethylparaben at respective concentrations of 0.313,0.313 mg/mL and 0.125 mg/mL showed the best inhibitory effect on Bacillus licheniformis with a 2(lg(CFU/g)) decrease 5.48(lg(CFU/g)) for the blank sample.Furthermore,the preservative combination indicated better inhibitory effect on Bacillus licheniformis in meat products,dairy products and juice during storage at 0-4 ℃.