Abstract:Due to the operation of cutting, fresh-cut fruits and vegetables are susceptible to microbial infection. In order to extend the shelf life of fresh-cut fruits and vegetables, the effects of the concentration and amount of available chlorine of slightly acidic electrolyzed water (SAEW) and the pressure level and holding time of high pressure (HP) on sterilization of fresh-cut carrots were studied through single factor experiment. Consequently, the combination treatment conditions were as follows: the concentration of available chlorine of slightly acidic electrolyzed water was 30mg/L and the amount of available chlorine of slightly acidic electrolyzed water was 200mL;the pressure level ranged from 100MPa to 400MPa, holding time was 5min and the total processing time was 15min. Fresh-cut carrots and apples were treated by the different combined treatments, and both brain heart infusion agar (BHIA) and vilolet red bile agar (VRBA) were used for the detection of E. coli. With the aim to explore the inactivation effects of combination treatment, during the detection, the slightly acidic electrolyzed water was chosen instead of HP sterilized water to do further test. The result shows that combined treatment can improve the efficiency of inactivation, but the enhancement was not significant at lower pressure. At 400MPa, HP treatment combined with SAEW displayed the most significant enhancement of inactivation efficiency, where E. coli could not be detected on fresh-cut carrot, but some E. coli was still detected on the fresh-cut apples in BHIA. When comparing the results in BHIA and VRBA, it can be seen that the SAEW showed significant lethal effect on E. coli, while HP showed both lethal and sublethal effect on E. coli.
