A similar procedure was followed for the active bioplastics prepared, but replacing the paper discs by a square piece (1 _ 1 cm2) of that material. Alternatively, bioplastic antimicrobial activity was tested by placing the specimen under the lid of the Petry dish, so
that the material is not in contact with the inoculated agar. In that case, inhibition would arise from the development of an antimicrobial atmosphere. Experiments were carried out in triplicate. The transport rate, from the bioplastic samples into water, of the two active agents studied was evaluated by immersion of 1 g bioplastic in 100 mL water and taking samples of water at 24, 48, 72 h, and finally after 1 week at room temperature. Formic acid release was determined by acid/base titration and, as for OEO release, concentration in water of phenolic compounds (thymol and carvacrol) contained in this biocide was determined by means of a colorimetric assay involving the Folin–Ciocalteu reagent (FCR), and expressed in gallic acid equivalent (mg/L).