MICROBIOLOGICAL QUALITY OF SHREDDED ENDIVE AS AFFECTED BY PRE-WASHING AND OZONATED WATER APPLIED AS DIPS OR SHOWER

The effect of washing shredded endive (Cichorium endivia L.) with 100 ppm NaOCl chlorinated, 0.4 ppm ozonated water, and tap water on microbial quality up was examined under storage up to 11 days at 5°C. In ozone treatments, two different washing procedures, dip or shower, were also tested. The implementation of a pre-washing step of trimmed endive was also studied. Psychotropic, mesophilic and Enterobacteriaceae were determined periodically. Ozone was a good substitute to chlorine but it depended on how it was applied. The efficiency of ozone water increased when it was applied as shower vs dips. Ozone shower treatment, and the chlorine treatment, reduced the psychrotrophic and mesophilic growth compared to water or ozone dips. These treatments did not exceeded the Spanish bacterial legal limits (7 log units) for aerobic bacteria and it was possible to extend the shelf-life to 11 days at 5°C. Water and ozone dip treatments were not marketable. The effectiveness of ozone dips was strongly dependent on the organic material the vegetables have. To increase this benefit in microbial group as psychrotropic, a previous step as a pre-washed, to reduce the organic material in the endive should be done. The implementation of a pre-washing step of trimmed endive heads resulted in a 0.7-1.3 log units reduction of the initial psychrotropic load. However, the use of chlorine or ozone (dip or shower) or a pre-washing step did not help to reduce the Enterobacteriaceae growth.