大气压冷等离子体处理对果蔬表面E.coli O157∶H7生物膜的清除作用

Antibacterial Activity of Atmospheric Cold Plasma Treatment Against E.coli O157:H7 Biofilms on Fruits and Vegetables

本文探究了大气压冷等离子体(ACP)处理对E.coli O157∶H7生物膜清除作用的最佳处理功率和处理时间,并进一步探究了ACP处理对E.coli O157∶H7生物膜的抗菌机制,利用场发射扫描电镜观察了ACP处理前后生物膜形态的变化,最后将ACP处理应用到四种果蔬表面E.coli O157∶H7生物膜的清除上。结果表明,在最佳处理功率400 W,最佳处理时间3 min下,ACP通过抑制胞外聚合物中多糖及蛋白质的合成与分泌来抑制生物膜的形成,并在处理当天分别对户太葡萄、圣女果、维多利亚青提及生菜这四种果蔬表面清除98.99%±0.38%、99.92%±0.20%、96.84%±0.18%、99.80%±0.23%的E.coli O157∶H7生物膜,在5 d内仍表现出了较好的抑制效果,延长了四种果蔬的贮藏期。结合感官评定结果,ACP处理虽对四种果蔬的色泽和感官品质略有影响,但仍能被大家所接受。综上,ACP处理可在基本不影响四种果蔬的色泽及感官品质前提下,对果蔬表面的E.coli O157∶H7生物膜有明显的清除效果。

The experiment explored the optimal power and time of ACP treatment on E.coli O157:H7 biofilms and its antibacterial mechanism.The morphological changes of biofilm before and after ACP treatment were also observed by field emission scanning electron microscope.Finally,ACP treatment was applied to the clearance of E.coli O157:H7 biofilms on the surface of four fruits and vegetables.The experimental results showed that ACP inhibited the formation of biofilms by inhibiting the synthesis and secretion of polysaccharides and proteins in the extracellular polymer at the optimal treatment power of 400 W and the optimal treatment time of 3 min.On the day of processing,98.99%±0.38%,99.92%±0.20%,96.84%±0.18%,99.80%±0.23%of the E.coli O157:H7 biofilms on the surface of the four fruits and vegetables,including Hutai grape,cherry tomato,Victoria green grape and lettuce,were respectively cleared,and exhibited good inhibitory effects within 5 days,extending the storage period of the four fruits and vegetables.Combined with the results of color and sensory evaluation,ACP treatment could remove E.coli O157:H7 biofilm on the surface of fruits and vegetables without affecting the sensory quality of the four fruits and vegetables.