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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL FOOD SAFETY OF FRESH AND FRESH-CUT PRODUCE Title: Developing Science-based Approaches to Reduce Produce Safety Risks at the End-user Levels

Author
item Luo, Yaguang

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2009
Publication Date: April 20, 2009
Citation: Luo, Y. 2009. Developing Science-based Approaches to Reduce Produce Safety Risks at the End-user Levels [abstract.].

Technical Abstract: An increasing number of food-borne illness outbreaks associated with the consumption of contaminated fresh and fresh-cut produce significantly impacted public health and consumer confidence. The urgent need to improve produce safety demands actions from growers, processors and consumers. The main objectives of this study were to determine the microbial profile of fresh tomatoes in the supply chain, and to assess the practicality and efficacy of consumer removal of the stem scar and underlying tissues in reducing food safety risks. Fresh tomatoes were obtained from retailers, wholesalers, and growers of various locations. Microorganisms on tomato surface, and internal tissues including pericarps, locules, and adjacent 5 mm segments along the central core from stem-scar to the blossom end were determined. The routes and mechanisms of pathogen internalization were investigated. We found that the vast majority of microorganisms are located on the stem-scars and in the underlying vascular bundle tissues within 15 mm of the stem-scar. Examination of tomatoes post-submerging in suspensions of fluorescent microspheres of similar size to Salmonella spp. revealed that the microspheres were concentrated in the vascular bundles connecting the stem-scar and internal tissues, suggesting that these vascular bundle tissues play a critical role in microbial internalization. It also supports our findings that internalized microorganisms are mostly concentrated in this region. Washing tomatoes with chlorinated water effectively inactivated the surface attached microorganisms, but failed to reduce the populations of internalized microorganisms. However, physical removal of the stem-scar and the underlying tissues, in conjunction with a surface wash achieved a significantly more effective reduction of both surface attached and internalized microorganisms. These results provide important information for consumers and food processors to develop science-based strategies and practices to reduce food safety risks associated with fresh tomatoes.

Last Modified: 7/24/2014
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