Effects of type and thickness of flexible packaging films on perforation by Plodia interpuntella

This study investigated the effect of perforation by the Indian meal moth (Plodia interpunctella) larvae on various flexible food-packaging films, in relation to their thickness and type. Among the various flexible packaging films, polyethylene (PE), aluminum foil (AF), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) were selected for this study due to their wide usage in food packaging. Based on their thickness, film penetration by P. interpunctella larvae was measured as in following order: PP, 20 μm; AF, 9 μm; PET, 12 μm; PP, 30 μm; PS, 30 μm; PE, 40 μm; PE, 35 μm; PS, 60 μm; and PET, 16 μm. P. interpunctella larvae rapidly penetrated through the packaging films regardless of their thickness and type. In particular, it was observed that PP of 20 μm and PS of 30 μm were completely penetrated by P. interpunctella larvae within 72 h, rendering thin PP and PS films less valuable as anti-insect packaging films. Our results show that the perforations by P. interpunctella larvae were observed in the thin films. These results imply that each packaging film has a marginal thickness against the perforations by P. interpunctella larvae.