Skip to main content

Penetration of Escherichia coli O157:H7 into Lettuce as Influenced by Modified Atmosphere and Temperature

The full text article is not available for purchase.

The publisher only permits individual articles to be downloaded by subscribers.

Abstract:

The effects of temperature and atmospheric oxygen concentration on the respiration rate of iceberg lettuce and Escherichia coli O157:H7 cells attachment to and penetration into damaged lettuce tissues were evaluated. Respiration rate of lettuce decreased as the temperature was reduced from 37 to 10°C. Reducing the temperature further to 4°C did not affect the respiration rate of lettuce. Respiration rate was also reduced by lowering the atmospheric oxygen concentration. Lettuce was submerged in E. coli O157:H7 inoculum at 4, 10, 22, or 37°C under 21 or 2.7% oxygen. Attachment and penetration of E. coli O157:H7 were not related to the respiration rate. The greatest numbers of E. coli O157:H7 cells attached to damaged lettuce tissues at 22°C at both oxygen concentrations. More cells were attached under 21% oxygen than under 2.7% oxygen at each temperature, but this difference was small. Penetration of E. coli O157:H7 into lettuce tissue was determined by immunostaining with a fluorescein isothiocyanate-labeled antibody. Under 21% oxygen, E. coli O157:H7 cells showed greatest penetration when lettuce was held at 4°C, compared to 10, 22, or 37°C, and were detected at an average of 101 μm below the surfaces of cut tissues. However, under 2.7% oxygen, there were no differences in degree of penetration among four incubation temperatures. The degree of E. coli O157:H7 penetration into lettuce tissue at 4 or 22°C was greater under 21% oxygen than under 2.7% oxygen; however, no difference was observed at 37°C. Conditions that promote pathogen penetration into tissue could decrease the effectiveness of decontamination treatments.

Keywords:

Document Type: Research Article

Affiliations: Center for Food Safety, Department of Food Science and Technology, University of Georgia, Athens, Georgia 30602, USA

Publication date: 2001-11-01

More about this publication?
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree 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