Effect of ozonized reverse osmosis plant water washing on microbial load of lychee

Abstract

The unpeeled bunches of lychee fruits were purchased from local market of Navsari, Gujarat, India and were divided into two lots; one was treated with ozonized reverse osmosis plant water and another was using non-ozonized reverse osmosis plant water. The washed samples were stored at cool place in ambient condition. The total plate count of these lychee fruits was recorded before and after washing treatment. The organoleptic evaluations of these treated samples were carried out using 9-point hedonic scale. The results indicated that the initial microbial load of lychee were recorded from 3580 cfu g(-1) to 10 cfu g(-1) and 560 cfu g(-1) for ozonized and non-ozonized reverse osmosis plant water washing treatment, respectively. However, the microbial load again increased and recorded above 3000 cfu g(-1) after 6 and 4 days of storage of lychee for ozonized and non-ozonized reverse osmosis plant water washing treatment, respectively. The overall acceptability score also reduced with respect to storage period. It was reduced from 8.3 for fresh lychee on the first day to less than 5 after 6 and 4 days of storage for ozonized and non-ozonized water washing treatment, respectively. Therefore, from this experiment, it can be concluded that ozonized water washing treatment can extend the storage life of lychee fruit by a week by reducing the microbial load; however it cannot eliminate the microbial load completely.