Study On The Combined Sterilization Method Of Pulsed Light Of Foodborne Microorganisms In Fruits And Vegetables

Fruits and vegetables are rich in vitamins and nutrients,which is increasingly sought after by consumers.However,due to foodborne microbial pollution situation,the outbreak of fruits and vegetables are frequently.Because fresh produce are not suitable for thermal sterilization.This paper studied the inactivation of pulsed light(PL)combination with antimicrobial washing and atomization means,respectively of inoculated salmonella on cherry tomato stem scar and blueberries surface,E.coli on Roman lettuce leaves and listeria on cantaloupe rind for non thermal sterilization,and the quality test of processed fruits and vegetables during storage was explored.After 30 s PL treatment,salmonella,E.coli and listeria on the surface of fruits and vegetables in the exposed group were decreased by 2.03,6.39 and 1.90 log CFU/g,respectively.Polyethylene films of 1Mli,2Mli and 3Mli thickness were used to package fruits and vegetables respectively.After 30 s PL,the bactericidal effect was not significantly different from that of the exposed group,and there is no blocking effect by PE film on PL concerned.9 kinds of antimicrobial solutions were used to rotate cleaning and sterilizing fruits and vegetables respectively,and the bactericide combined with PL was selected to have a better sterilization effect.The sterilization effect of first PL and then washing was better than that of first washing and then PL.After first PL and then OCHAL washing(PL-OCHAL)process,the salmonella,escherichia coli and listeria on the surface of fruits and vegetables decreased by 2.77,6.31 and 2.05 log CFU/g,respectively.After PL-OCHAL treatment,tomatoes were stored at 10℃ for 21 days.Only the hardness on the 21st day was significantly lower than that of the control group,and there was no significant difference in color difference,ascorbic acid content and antioxidant performance.Lettuce was stored at 4℃ for 7 days.The hardness of lettuce decreased rapidly in 3-5 days,and there was no significant difference in color difference,ascorbic acid content and antioxidant performance between the control group and the control group during storage period.The cantaloupe rind was stored at 4℃ for 7 days,and hardness and color difference were not significantly different from the control group.After being sterilized with PL and then atomized with 1%FA and stored at 10℃ for 21 days,the salmonella inoculated in the fruit stem scar of cherry tomatoes decreased by 4.17 log CFU/g,and the hardness,ascorbic acid content,antioxidant and color difference of tomatoes showed no significant changes compared with the control group.During the 7-day storage period,the escherichia coli on the surface of Roman lettuce decreased by 6.52 log CFU/g,and there was no significant change in hardness and chlorophyll content.Via 60 s PL assist with 5%hydrogen peroxide+10 PPM TO wash,the salmonella inoculated on the surface of blueberries decreased by 5.07 log CFU/g on 7th days at 10℃.While 60 s PL and 60 s 5%hydrogen peroxide+10 PPM TO wash were used separately,the bactericidal effect is less than 2 log.After combination sterilization,the hardness,antioxidant(ORAC),total phenol and chroma of blueberries were showed no significant changes compared with the control group.