Biocontrol of Escherichia coli O157:H7 exerted by endogenous microflora and oleoresins in minimally processed lettuce and carrot
The objectives of this study were to analyse the effectiveness of native microflora of lettuce and carrot in controlling Escherichia coli O157:H7 and to evaluate the technological application of oregano and rosemary to control E. coli in vegetables stored at 8?C and 20?C. The interaction between the background microflora of lettuce and carrot with E. coli O157:H7 was observed at 20?C. In samples stored at 8?C, the temperature factor masked any bacteriostatic effects exerted by native microflora on E. coli. For oregano and rosemary, the highest concentrations were needed to restrict E. coli in lettuce and carrot. However, low sensory acceptability was obtained. Pathogen inhibition was more important at high temperature. The effectiveness of oleoresins was the result of factor associations such as concentrations and storage temperatures.
Keywords: biopreservatives, native microflora, oreganum, pathogen control, rosemary, oregano, vegetables, lettuce, carrots, Escherichia coli, E coli, oleoresins, storage temperature