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

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.