The presence of persistent coliform and E. coli contamination sequestered within the leaves of the popular fresh salad vegetable “Jarjeer / Rocket” (Eruca sativa L.).

Russell, Dennis J.; Abdul Majid, Sarah; Tobias, Daniel

doi:10.21608/eajbsg.2010.16702

The presence of persistent coliform and E. coli contamination sequestered within the leaves of the popular fresh salad vegetable “Jarjeer / Rocket” (Eruca sativa L.).

Document Type : Original Article

Authors

¹ Department of Biology and Chemistry, American University of Sharjah, PO Box 26666, Sharjah, United Arab Emirates

² Department of Biology and Chemistry, American University of Sharjah, PO Box 26666, Sharjah, United Arab Emirates.

10.21608/eajbsg.2010.16702

Abstract

Tests of Jarjeer/rocket (Eruca sativa L.) salad greens after multiple washings in water and mild disinfectant revealed a significant number of sequestered total coliforms and E. coli remained in the fresh greens. Presumptive tests of 64 locally purchased fresh jarjeer greens resulted in finding 100% of the samples were contaminated by coliforms and E. coli. Jarjeer greens had 2,509,273 CFU/g and 224,250 E. coli/g when washed once. Washing the greens three times reduced the number of CFU by 95% and E. coli by 83%, but E. coli counts remained high 9,741 / g or 292,230 per 30 g normally eaten portion. After macerating the thrice washed jarjeer the number of CFU increased to 2,129,774 / g and E. coli 56,292/g, which indicated the bacteria are sequestered in the leaves and could not be washed off. Disinfection with diluted chlorine bleach reduced CFU by 68% and E. coli by 84%, but upon maceration CFUs increased from 42,059/g to 833,812/g and E. coli from 5/g to 2,150/g, which indicates washing with a disinfectant cannot rid the greens of coliforms. Counts on parsley and lettuce were significantly lower than on jarjeer. Results indicate there is sequestered fecal contamination of fresh jarjeer salad greens that remained on and inside epidermal cells even after multiple washings. These data show that there is probably a persistent health threat when eating these fresh salad greens, but further testing for the presence of Salmonella and other pathogens is required.

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