A device for quick evaluation resistance of packaging films to penetration by storage insects
Abstract: A quick test method was developed to evaluate penetration of storage insects through packaging films. The developed method consisted of two identical glass cylinders and a wire mesh placed on top of the film to be tested placed together among the two cylinders. The efficacy of the method was evaluated using Rhyzopertha dominica (L.), 10-15 d adults placed in the test device. Exposure periods of insects to the test films consisting of office paper (80 g/m2) (110 μm thick), flour package paper (150 μm thick), aluminum foil (20 μm thick), laminate (120 and 150 μm thick), Whatman No. 1 (200 μm thick), Whatman No. 44 (170 μm thick), Whatman No. 50 (110 μm thick) and polyethylene (10 and 20 μm thick) were 12, 18, 24, 48 and 72 h in the cell with wire mesh (No. 25). Penetration was also evaluated for 24, 48, and 72 h. Penetration by R. dominica adults increased with increasing exposure periods. The thickness and the type of the films played an important role on resistance of insects to penetration. R. dominica penetrated to all tested films within 24 h exposure except the laminate of 150 μm. Significant differences were found in the ability of R. dominica to penetrate the films with and without using wire mesh in the test device. A possible explanation for the speed that insects penetrated may be because of the wire mesh positioned adjacent to the test film. Given test apparatus was simple to construct and less expensive than a device that used metal sections, since it enabled evaluation of the tested packaging films within extremely short exposure times.