4x6 - different levels and that the E coli cells were able...

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Card #5 Class: Lab A Journal: Agricultural Ressearch Title: ARS Scientist Study The Ins and Outs of E.Coli Contamination Author: Ann Perry Date of Article: April 2011 Pages: 6-7 Summary: Of the hundreds of strains of E. coli that exist, food safety experts are concerned that the few strains that are pathogenic coulld be taken up by plants through the roots along with nutrients and water. This could allow the bacterium to infiltrate the plant’s vascular system and increase the incidence to foodborne illness. Researchers track the pathogen’s journey from field to harvest by by modifying several strains of E. coli to contain a gene for fluorescence. The modified bacteria included highly pathogenic strains of E. coli O157:H7 as well as nonpathogenic strains. The fluroescence gene was placed at a specific location within the chromosome structure of the bacteria where it would not interfere with any essential metabolic functions or stress responses of the cells. The researchers first confirmed that the pathogenic E. coli could survive in soil up to 21 days at
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Unformatted text preview: different levels and that the E. coli cells were able to migrate into the roots of the spinach plants. In addition, the researchers examined baby spinach plants over the coarse of 28 days after germination to see whether any of the E. coli strains were taken up past the roots and into the plant’s interior structure. For this part of the study they grew baby spinach in pasteurized soils and and hydrophonic media. The researchers found that at day 28, there was no evidence that E. coli had become internalized in the leaves or shoots of baby spinach plants grown in soil. E. coli was detected in hydrophonically grown spinach samples analyzed 14 and 21 days after germination but at 28 days the bacteria levels were very low. The scientists believe that the results confirm that E. coli can grow in soils but that it is highly unlikely that foodborne illness can result from the bacterium becoming internalized through roots in leafy produce....
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This note was uploaded on 03/24/2012 for the course BMS 127 taught by Professor Meyer during the Fall '11 term at Santa Barbara City.

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