According to a USDA statement, the tests are designed to ensure that farmers with organic status are not breaching regulations relating to it.
The first USDA regulations regarding the organic sector were issued in 2002, but according to the Wall Street Journal, the responsibility for performing periodic residual testing was left largely in the companies' hands.
While the USDA regulations mandate that all organic growers undergo an initial examination to secure their status, the regulations requiring they be regularly reevaluated have so far been lacking.
According to the WSJ, there are currently less than 100 accredited agents allowed to complete the tests. They serve some 30,000 organic growers, internationally, who sell their foods in the US.
The USDA will reportedly allow those agents to determine the 5% of the farms that will be tested each year, as mandating which facilities are tested would increase costs.