The different solutions were spiked
on pieces of paper that were placed into the test pouch as internal
active labels, as a proof-of-concept experiment. In the second stage,
the active agents were incorporated into the film, and a piece of
active film was placed into the test pouch. In the first stage, paper
also helped in reducing the condensation of water into the pouch,
that otherwise would had caused brown spots in the mushrooms
and the subsequent disruption of the experiment.