The effect of thermal, chlorine and ozone treatments on survival of Escherichia coli and Salmonella spp. in açai berries

Abstract

Açai berries (Euterpe oleracea Mart.) have a high natural microbial load that can compromise the quality of their products. In this study, test microorganisms were inoculated on raw açai berries in drip trials, with five strains of Salmonella spp. and E. coli, separately. Açai berries sanitizing processes were: i) chlorination with 200 mg.L -1 for a period of 15 min; ii) blanching at 80 °C for 10 s (regional legislation); iii) blanching at 90 °C for 10 s; iv) aqueous ozonation at 4 mg.L -1 for 5 min; and v) washing with distilled water for 15 min as control treatment. Thermal treatment at 90 °C 10 s achieved the highest efficiency in reducing counts of E.coli (3.0 ± 0.8 log CFU.mL -1 ). In Salmonella spp., all sanitizing treatments were similar and better than simple washing with water. Thus, blanching of açai berries at 90 °C 10 s, with immediate cooling with chlorinated water (50 mg.L -1 ), is an alternative process for sanitization for açai berries, considering the application of good manufacturing practices.