Superficial growth of Aspergillus ellipticus on lignocellulosic materials

Lignocellulosic materials used in the food industry as containers or packaging can suffer fungal biodeterioration. For this reason, the aim of this study was to evaluate the superficial growth of Aspergillus ellipticus on lignocellulosic materials of food containers and packaging. A strain of A. ellipticus was selected for its high productivity of lignocellulolytic enzymes. Fragments the diameter of a 110 mm Petri dish were cut from six types of lignocellulosic materials used as supports: coated cardboard, uncoated cardboard, corrugated cardboard, kraft paper, cupcake wrapper and Whatman 5 filter paper (positive control). The thickness (µm) and initial pH were measured for each material by contacting 2 g of material with 100 mL of distilled water at 15 °C and 40 °C and 10 µL of a spore suspension (10⁶ spores/mL) was inoculated and incubated at 32 °C and 87% relative humidity in a desiccator with saturated barium solution. For 21 days, the diameter of the colony (mm) was measured growing on lignocellulosic materials. The pH of the materials was between 7.2 and 7.4, considering them neutral materials. The growth of the fungal colony was between 2 mm and 38.6 mm, being higher on filter paper, followed by kraft paper, corrugated cardboard, uncoated cardboard, coated cardboard and cupcake wrapper. It is concluded that fungal biodeterioration of lignocellulosic packaging material for food can occur in conditions similar to those of tropical climates.