Impact of Oregano and Rosemary Oleoresins on Native Microflora and E. coli 0157:H7 Growth on Sliced and Grated Carrots

摘要

The microbiological safety of fresh produce has been a cause for concern among consumers and within the food industry. Considering the demand for current information, the biocontrol exerted on E. coli by the native microflora on carrots was studied. Oregano and rosemary oleoresins were applied and E. coli 0157:H7 was inoculated at a medium level (4-5 log_(10) CFU/g) on sliced and grated carrots. Samples were stored at 20 and 10 deg C for 96 h to monitor changes in native microflora and pathogen growth. Biocontrol exerted on E. coli 0157:H7 by the native microflora was not significant at storage temperatures of 20 and 10 deg C in both types of processed carrot. The use of oregano and rosemary at higher concentration exerted an inhibitory effect on the native microflora of sliced carrot and on E. coli 0157:H7 growth in sliced and grated carrots. However, sensory analysis revealed that acceptance was inversely related to the concentration of the oleoresins used. Inhibition of the pathogen was more evident at 20 than at 10 deg C in both types of processed carrot.The bacteriostatic effect of oleoresins on the pathogen could be enhanced by synergistic effects together with other preservation technologies.