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International Journal of Microbiology
Volume 2013, Article ID 398320, 5 pages
Research Article

Effect of Citrus Byproducts on Survival of O157:H7 and Non-O157 Escherichia coli Serogroups within In Vitro Bovine Ruminal Microbial Fermentations

1Department of Animal Science, Iowa State University, Ames, IA, USA
2Animal Science Department, University of Nebraska, Lincoln, NE, USA
3Food and Feed Safety Research Unit, ARS, USDA, College Station, TX 79403, USA
4Livestock Issues Research Unit, ARS, USDA, Lubbock, TX 77845, USA
5Department of Animal and Dairy Sciences, Mississippi State University, Mississippi State, MS, USA
6Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
7Department of Animal and Food Sciences, Texas Tech University, Lubbock, TX, USA

Received 12 November 2012; Accepted 8 January 2013

Academic Editor: Giuseppe Comi

Copyright © 2013 Heather A. Duoss-Jennings et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Citrus byproducts (CBPs) are utilized as a low cost nutritional supplement to the diets of cattle and have been suggested to inhibit the growth of both Escherichia coli O157:H7 and Salmonella. The objective of this study was to examine the effects in vitro that varying concentrations of CBP in the powdered or pelleted variety have on the survival of Shiga-toxin Escherichia coli (STEC) serotypes O26:H11, O103:H8, O111:H8, O145:H28, and O157:H7 in bovine ruminal microorganism media. The O26:H11, O111:H8, O145:H28, and O157:H7 serotypes did not exhibit a change in populations in media supplemented with CBP with either variety. The O103:H8 serotype displayed a general trend for an approximate reduction in 5% powdered CBP and 20% pelleted CBP over 6 h. There was a trend for reductions in populations of a variant form of O157:H7 mutated in the stx1 and stx2 genes in higher concentrations of CBP. These results suggest that variations exist in the survival of these serotypes of STEC within mixed ruminal microorganism fluid media when supplemented with CBP. Further research is needed to determine why CBPs affect STEC serotypes differently.