Evaluation of ozone efficiency as a sanitizer on minimally processed vegetables. / Avaliação da eficiencia do ozonio como sanitizante em hortaliças folhosas minimamente processadas.




Minimally processed fruits and vegetables are sold already washed, peeled, cut or sliced, sanitized, packaged and cold-storaged. Consumption of this kind of food has increased markedly in the last decades due to people interest for fresh and practice foods. High handling during its processing, increasing of its shelf-life and absence of remarkable technologic barriers against microorganisms (water activity, pH, thermal treatment, etc.) are factors that facilitate contamination risks in these products. Sanitizers commonly used are chlorine compounds due to their efficiency and low cost. However, several works report the production of toxic residues led by chlorine compounds in rinse water and vegetables. Moreover, the 15 minutes contact time required by chlorine compounds to their efficient activity can be considered long in a great-scale industrial processing. Thus the ozone gas becomes an alternative due to its sanitizing efficiency in low dosages, in a short time and with no residual toxic compounds. Ozone concentrations of 0,5, 1,0 and 1,5 mg.L -1 per 1 minute was used as sanitizer during minimal processing of iceberg and curly lettuce (Lactuca sativa L.), rocket salad (Eruca sativa Mill.) and watercress (Nasturtium officinale R. Br.) in comparison with chlorine to determine the most efficient treatment under microbiological and sensorial aspects. Total coliforms, moulds and yeasts and psychrotrophics counts were done. The data revealed that vegetables rinsed in tap water had reduced all of microorganisms? populations studied by 1 log. Ozone in concentrations 1.0 and 1.5 mg.L-1 showed better performance than chlorine on total coliforms, moulds and yeasts populational reduction. The same performance was noticed in the last day of analysis. Sanitizing treatments had no relevant influence on vegetables sensorial performance.


ozone processamento minimo minimal processing sanitização chlorine cloro ozonio hortaliças vegetables sanitation

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