Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang, China.
Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang, China; Fuli Institute of Food Science, Zhejiang University, Hangzhou, China.
Int J Food Microbiol. 2019 Dec 2;311:108329. doi: 10.1016/j.ijfoodmicro.2019.108329. Epub 2019 Aug 27.
This study evaluated the synergetic inhibitory effects of ultrasound and nisin/carvacrol on spore germination, outgrowth, and subsequent growth of vegetative cell of Bacillus subtilis in laboratory medium and milk. Ultrasound pretreatment (3.33 W/mL, 15 min) and nisin/carvacrol (0.01%, 0.02%) synergistically inhibited spore germination, outgrowth, and vegetative growth of spores in laboratory medium. Whereas no such inhibitory effect was observed in milk even with a 10-fold increase in the concentration (1%) of nisin. Flow cytometry analysis showed that the germination capacities of ultrasound pretreated spores combined with nisin/carvacrol (67.3% and 30.5%, respectively) was lower than that of the untreated spores (95.1%). These results quantitatively revealed the inhibitory effect of the combined treatments which were confirmed by phase-bright spore observations at single cell level. In general, the current work identified the combined ultrasound-carvacrol treatment as an effective strategy to control spores and vegetative cells of B. subtilis in the laboratory medium and milk during abusive storage.
本研究评估了超声与乳链菌肽/香芹酚协同抑制枯草芽孢杆菌孢子萌发、生长及随后营养细胞生长的效果。在实验室培养基和牛奶中，超声预处理（3.33 W/mL，15 min）与乳链菌肽/香芹酚（0.01%，0.02%）协同抑制孢子萌发、生长及营养细胞生长。而即使在牛奶中乳链菌肽浓度增加 10 倍（1%）也未观察到这种抑制作用。流式细胞术分析表明，与未经处理的孢子相比，经超声预处理后再与乳链菌肽/香芹酚（分别为 67.3%和 30.5%）联合处理的孢子的萌发能力较低（分别为 95.1%）。这些结果从定量上揭示了联合处理的抑制效果，单细胞水平的明场孢子观察结果对此进行了验证。总的来说，本研究在恶劣储存条件下，在实验室培养基和牛奶中，确定了超声-香芹酚联合处理作为控制枯草芽孢杆菌孢子和营养细胞的有效策略。
