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Research Project: MICROBIAL ECOLOGY AND SAFETY OF FRESH ON-FARM ORGANICALLY GROWN PRODUCE Title: Effect of curli expression and hydrophobicity of E. coli O157:H7 on attachment to fresh produce surfaces

Authors
item Patel, Jitu
item Sharma, Manan
item Ravishankar, Sadhana -

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 16, 2010
Publication Date: February 8, 2011
Repository URL: http://hdl.handle.net/10113/50453
Citation: Patel, J.R., Sharma, M., Ravishankar, S. 2011. Effect of curli expression and hydrophobicity of E. coli O157:H7 on attachment to fresh produce surfaces. Journal of Applied Microbiology. 110:737-745.

Interpretive Summary: Bacterial attachment to produce surface is the first step of contamination event. We evaluated the effect of curli expression and cell hydrophobicity on attachment of E. coli O157:H7 to intact and cut lettuce and cabbage surfaces. Curli expressing E. coli O157:H7 strains 4406 and 4407 were more hydrophobic and attached to intact and cut cabbage surfaces at higher numbers than that of other strains. Differences in E. coli O157:H7 populations attached to these produce surfaces were not significant (P > 0.05). All E. coli O157:H7 strains attached rapidly on intact and cut produce surfaces. E. coli O157:H7 attached preferentially to cut surface of all produce; however, the difference between E. coli O157:H7 populations attached to intact and cut surfaces was similar (P > 0.05) in most cases. E. coli O157:H7 attachment and attachment strength to intact and cut produce surfaces increased with time. Increased attachment of E. coli O157:H7 on cut surfaces necessitates effective produce wash to kill E. coli O157:H7 on produce. Understanding the attachment mechanisms of E. coli O157:H7 to produce surfaces will be helpful in developing new intervention strategies to prevent produce outbreaks.

Technical Abstract: Aim: To investigate the effect of curli expression on cell hydrophobicity, biofilm formation, and attachment to cut and intact fresh produce surfaces. Methods and Results: Five E. coli O157:H7 strains were evaluated for curli expression, hydrophobicity, biofilm formation, and attachment of E. coli O157:H7 strains to intact and cut fresh produce (cabbage, Iceberg lettuce and Romaine lettuce) leaves were determined. Biofilm formation was stronger when E. coli O157:H7 were grown in diluted TSB (1:10). Curli expressing E. coli O157:H7 strains 4406 and 4407 were more hydrophobic and attached to intact and cut cabbage surfaces at higher numbers than that of other strains. Differences in E. coli O157:H7 populations attached to these produce surfaces were not significant (P > 0.05). All E. coli O157:H7 strains attached rapidly on intact and cut produce surfaces. E. coli O157:H7 attached preferentially to cut surface of all produce; however, the difference between E. coli O157:H7 populations attached to intact and cut surfaces was similar (P > 0.05) in most cases. E. coli O157:H7 attachment and attachment strength (SR) to intact and cut produce surfaces increased with time. Conclusions: Curli producing E. coli O157:H7 strains attaches at higher numbers on produce surfaces. Increased attachment of E. coli O157:H7 on cut surfaces necessitates effective produce wash to kill E. coli O157:H7 on produce. Significance and Impact of the Study: Understanding the attachment mechanisms of E. coli O157:H7 to produce surfaces will be helpful in developing new intervention strategies to prevent produce outbreaks.

   

 
Project Team
Patel, Jitu
Sharma, Manan
Nou, Xiangwu
Mulbry, Walter
Shelton, Daniel
Millner, Patricia
 
Publications
   Publications
 
Related National Programs
  Food Safety, (animal and plant products) (108)
 
 
Last Modified: 05/21/2013
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