Cross-contamination is the term used when pathogens (bacteria, viruses, parasites) that may result in food borne illnesses (food poisoning) are transferred from:

1. a surface to another surface - e.g. using the same cutting board to prepare raw meat and cooked meat 

Systems of mature trees and shrubs are covered with blemishes that signal age: cankers, seams, burls, butt scars, sterile conks, and protrusions in the form of bracket fungi.

In an effort to protect the Great Smoky Mountains National Park forest from disease-carrying pests, park officials have proposed a new regulation that would prohibit campers from bringing firewood into the park unless it’s certified. 

If passed, the new regulation would only allow visitors to bring in firewood that has been heat-treated and bundled with a certification stamp by the U.S. Department of Agriculture or a state department of agriculture. Certified firewood will be available for purchase at the campgrounds inside the park.