Effect of Micro-nano Bubbles Combined with Advanced Oxidation Process (NaOCl/ UVC) on Reducing of Microbial Contamination of Fresh-cut ‘Cos’ Lettuce

An increased number of outbreaks associated with fresh-cut produce brought the necessity to deal with microbial decontamination methods of the fresh-cut products. This research aimed to study the effect of micro-nano bubbles combined with advanced oxidation process (NaOCl/UVC) on reducing of microbial contamination of fresh-cut ‘cos’ lettuce. ‘Cos’ lettuce was sanitized with water (control), sodium hypochlorite (200 ppm), and micro-nano bubbles (MNBs) combined with NaOCl/UVC (200 ppm, 30W UVC) for 5 min. Washed lettuce were packed in clam shell box then stored at 4 °C for 9 days. Total bacteria counts, coliform counts and yeast & mold on fresh-cut ‘cos’ lettuce after washed were reduced by 1–2 log CFU/g using MNBs + NaOCl/UVC, which was bettet than that achieved using 200 ppm NaOCl. The quality of washed lettuce were also unaffected by treatment with MNBs + NaOCl/UVC as indicated by no changes of leaf color (L*, a*, b* and Hue value) during storage. However, lettuce washed with MNBs + NaOCl/UVC showed a higher level of phenolic compound as compare with the control at day 6 and 9 of storage. In conclusion, this new technology had the potential to reducing of microbial contamination of fresh-cut ‘cos’ lettuce during cold storage and improve product safety, while not affecting quality throughout the shelf life of the finished products