Study On The Bactericidal And Preservation Effects Of Saew And UV-LED On Coriander

Slightly acidic electrolyzed water(SAEW)has a pH of 5.0 to 6.5,and its main bactericidal component is HCIO,which is recognized as a green,residue-free and highly effective bactericide.The UV-Light Emitting Diode(UV-LED)has a wavelength of 280 nm and has an inactivating effect on pathogenic microorganisms.In this paper,SAEW and UV-LED were applied on the surface of coriander to study the bactericidal effect of Salmonella and Escherichia coli O157 on the surface of coriander,and to explore the effect of both treatments on the sensory and nutritional quality of coriander during storage at 4℃.1.Study on the sterilization effect of UV-LED and SAEW on the surface of coriander.SAEW(pH=5.0~6.5)not only inactivate Salmonella and Escherichia coli O157 on the surface of coriander,but also can achieve a good sterilization effect after1 minute treatment.The change trend is the same as the change trend of physical and chemical properties after SAEW treatment.In the case of mechanical stirring,SAEW with effective chlorine concentrations of 20 mg/L,40 mg/L and 60 mg/L could reduce Salmonella on the surface of coriander by 1.3,1.53 and 1.64 log CFU/g after 1 min of treatment,and Escherichia coli O157 by 1.11,1.45 and 1.78 log CFU/g,respectively.The irradiation intensity of 240μW/cm~2 UV-LED treatment for 30 min reduced the Salmonella and Escherichia coli O157 on the surface of coriander by 1.15 log CFU/g and 1.22 log CFU/g,respectively.At the same time,it was found that the bactericidal kinetics of Salmonella and Escherichia coli O157 on the surface of coriander by SAEW and UV-LED sterilization could be described by first-order kinetic Weibull model,with the determination coefficient R~2 greater than 0.9.2.The bactericidal effect of SAEW combined with UV-LED on the surface of coriander was observed by sem.The combined treatment of SAEW and UV-LED significantly enhanced the bacteria-eliminating rate of Salmonella and Escherichia coli O157 on the surface of coriander compared with the single treatment.When SAEW(ACC=60 mg/L,treatment time=5 min)and UV-LED(irradiation intensity=240μW/cm~2,treatment time=30 min)were combined to treat Salmonella and Escherichia coli O157 on the surface of coriander,the sterilization rate increased by0.86 log CFU/g and 0.56 log CFU/g,respectively,compared to SAEW alone,as well as 1.57 log CFU/g and 1.35 log CFU/g,respectively,compared with UV-LED alone.At the same time,it was found that the two can effectively inhibit the growth of microorganisms during the storage of coriander at 4℃,and the inactivation mechanism of Salmonella and Escherichia coli O157 were analyzed.3.Effect of SAEW and UV-LED on sensory evaluation and quality of coriander.SAEW and UV-LED treatment could not only slow down the decrease of sensory evaluation of coriander during storage at 4℃;Moreover,it can effectively slow down the attenuation of vitamin C and chlorophyll content,and can significantly inhibit the increase of weight loss rate and malondialdehyde content,and has no significant effect on its soluble solids and color.At the same time,UV-LED and combined treatment can effectively increase the accumulation of total phenol content and the change of DPPH clearance rate,and improve its antioxidant activity.Therefore,SAEW and UV-LED treatment can not only reduce the microorganisms on the surface of vegetables,but also improve the quality of storage.It has a wide application prospect in ensuring the safety of vegetables.