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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL FOOD SAFETY OF FRESH AND FRESH-CUT PRODUCE Title: Investigation of pathogen infiltration into produce using Xradia Bio MicroCT

Authors
item Zhou, Bin -
item Feng, Hao -
item Luo, Yaguang

Submitted to: Annual Meeting of the Institute of Food Technologists
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2011
Publication Date: June 11, 2011
Citation: Zhou, B., Feng, H., Luo, Y. 2011. Investigation of pathogen infiltration into produce using Xradia Bio MicroCT. [abstract]. Annual Meeting of the Institute of Food Technologists.

Technical Abstract: The internalization of human pathogens into plant tissues has received significant attention. Human pathogens can infiltrate plant tissue through stomata, cut edges, wounds on produce, or the plant vascular system. The nondestructive X-ray computed microtomography (MicroCT) technique is an X-ray–based technique for taking images of 3D structures. MicroCT has been widely applied for quantification of the 3D micro architecture of different scaffolds made from ceramics, polymers, and glasses and mineralized tissues. In this study, MicroXCT was used to investigate the internal structure of fresh produce and the infiltration of contrast agents into plant tissues. Fresh pieces of spinach, romaine lettuce, pepper, and tomato were inserted into polyimide tubing, and scanned with a MicroXCT at 0.5'~4'. An X-ray tube with a tungsten anode setting of 40 kV at 4 W was adapted for the transmission X-ray imaging of the specimens. The 3D images were constructed using 720 images taken at 10 s per image using the Xradia scanner. Further, leaf pieces (2 mm ' 10 mm) of spinach infiltrated with micro golden particles, and tomatoes infiltrated with 0.25 mL of 120 mg/mL potassium iodine absorbed through the stem scar were scanned using MicroXCT to mimic the penetration of human pathogens. The MicroXCT images provided a clear view of the internal structure of the selected vegetables. The images taken from the sample cross section showed that the potassium iodide concentrated on vascular bundles, and infiltrated into tomato tissue along the vascular bundles. The images of inoculated tomato also showed notable contrast between the gold particles and spinach leaf tissues. Therefore, the MicroXCT may be used as a tool to visualize the infiltration pathway of human pathogens into fresh and fresh-cut produce.

Last Modified: 10/23/2014
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