A mycological investigation of phane, an edible caterpillar of an emperor moth, Imbrasia belina

Abstract

Phane worm (an edible larval stage of the emperor moth Imbrasia belina Westwood) is an important food source, and its harvesting is an economic activity in rural Botswana. When the larva is feeding on leaves and later during processing, phane gets contaminated with fungi from the leaves and soil. We examined 73 jars, each containing approximately 608 g (±0.25 g) of processed phane stored under laboratory conditions (temperature range 20 to 24°C and 50 to 80% relative humidity) and combined intestinal contents of five phane squeezed into each of 74 Duran bottles for fungi. Ninety seven percent of 74 samples of intestinal contents and 57.5% of 73 laboratory-stored phane were positive for either molds and/or yeasts. Yeast population in intestinal contents ranged from 2 x 101 CFU/g to 5 x 103 CFU/g, whereas molds ranged from 1 x 101 CFU/g to 2 x 102 CFU/g. Laboratory-stored phane had a mold population of 1 X 102 CFU/g to 6 X 105 CFU/g. Species of Chaetomium 13.8%, Aspergillus 12.4%, Fusarium 5.5%, and Mucor racemosus 4.1% were the most prevalent in intestinal contents of phane, whereas Aspergillus 42.1%, Penicillium 33.9%, and Mucorales 5.7% were predominant in laboratory-stored phane. The important mycotoxigenic fungi A. flavus, A. parasiticus, A. ochraceus, P. aurantiogriseum, P. citrinum, and P. verrucosum were isolated mainly from the laboratory-stored phane. The genera isolated from both intestinal phane contents and laboratory-stored phane were Alternaria, Aspergillus, Chaetomium, Drechslera, Fusarium, Mucor, Phoma, and Penicillium, suggesting recontamination of phane during drying and storage.