Skip to main content

Preharvest Internalization of Escherichia coli O157:H7 into Lettuce Leaves, as Affected by Insect and Physical Damage

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.

Abstract:

Environmental pests may serve as reservoirs and vectors of zoonotic pathogens to leafy greens; however, it is unknown whether insect pests feeding on plant tissues could redistribute these pathogens present on the surface of leaves to internal sites. This study sought to differentiate the degree of tissue internalization of Escherichia coli O157:H7 when applied at different populations on the surface of lettuce and spinach leaves, and to ascertain whether lettuce-infesting insects or physical injury could influence the fate of either surface or internalized populations of this enteric pathogen. No internalization of E. coli O157:H7 occurred when lettuce leaves were inoculated with 4.4 log CFU per leaf, but it did occur when inoculated with 6.4 log CFU per leaf. Internalization was statistically greater when spinach leaves were inoculated on the abaxial (underside) than when inoculated on the adaxial (topside) side, and when the enteric pathogen was spread after surface inoculation. Brief exposure (∼18 h) of lettuce leaves to insects (5 cabbage loopers, 10 thrips, or 10 aphids) prior to inoculation with E. coli O157:H7 resulted in significantly reduced internalized populations of the pathogen within these leaves after approximately 2 weeks, as compared with leaves not exposed to insects. Surface-contaminated leaves physically injured through file abrasions also had significantly reduced populations of both total and internalized E. coli O157:H7 as compared with nonabraded leaves 2 weeks after pathogen exposure.

Document Type: Research Article

Affiliations: 1: Center for Food Safety, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA. mericks@uga.edu 2: Center for Food Safety, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA 3: Department of Entomology, P.O. Box 748, University of Georgia, Tifton, Georgia 31793, USA 4: Center for Food Safety, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA; National Institute of Microbial Forensics and Food and Agricultural Biosecurity, Oklahoma State University, Stillwater, OK 74078, USA 5: Center for Food Safety, 1109 Experiment Street, University of Georgia, Griffin, Georgia 30223, USA; Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, 5100 Paint Branch Parkway, College Park, MD 20740, USA 6: Department of Crop and Soil Sciences, University of Georgia, Griffin, Georgia 30223, USA

Publication date:

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more