Better check those vendors before you sell it to your guests TR's post explains,
Now a team of chemists at McMaster University in Ontario have published a paper in Analytical Chemistry that describes a new biomonitoring technique using treated paper on a stick that can quickly identify trace amounts of pesticides in your chicken soup, or your first early morning cup of joe.
As reported in R&D:
The scientists describe the development of a new paper-based test strip that changes color shades depending on the amount of pesticide present. In laboratory studies using food and beverage samples intentionally contaminated with common pesticides, the test strips accurately identified minute amounts of pesticides. The test strips, which produced results in less than 5 minutes, could be particularly useful in developing countries or remote areas that may lack access to expensive testing equipment and electricity, they note.