Abstract

LUNA GUEVARA, María L et al. Efficacy of disinfection treatments using essential oils and ultrasound on tomato fruits inoculated with Escherichia coli and impact on antioxidant activity. Rev. argent. microbiol. [online]. 2015, vol.47, n.3, pp.251-255. ISSN 0325-7541.  http://dx.doi.org/10.1016/j.ram.2015.04.004.

Fresh produce often harbors a great number of microorganisms; hence, its growing demand may constitute a risk for consumers. The aim of this study was to evaluate the efficacy of several disinfection procedures against enterotoxigenic Escherichia coli (ETEC) inoculated on tomato fruits and the conservation of the antioxidant properties of these disinfected fruits. Fruits were immersed for 5 or 10 min in oregano or thyme essential oil dispersions (5, 10 ppm), with or without ultrasound treatment. Antioxidant activity of disinfected fruits was determined as the ability to scavenge 2,2-diphenyl-1-pricrylhydrazyl (DPPH) radicals and was reported as percentage of inhibition (% I). The most efficient disinfectant treatments showing significant differences (p ≤ .05) between the reductions log₁₀ CFU/g (S) of ETEC were those using 10 ppm oregano for 10 min, with S = 3.05 in individual treatments and S = 4.03 in mixed treatments. The highest % I was obtained with individual sonication treatments (69.52 and 72.48), while in combined treatments the % I values increased with thyme oil 5 ppm and ultrasound for 5 min (51.27%) and 10 min (53.31%).

Keywords : Essential oils; Antioxidant activity; Ultrasound; Tomato; Escherichia coli; Assisted disinfection.

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