The microbiology of phane, an edible caterpillar of the emperor moth, Imbrasia belina

Abstract

The larvae of Imbrasia belina (Westwood) are cooked and sun dried to make a product known as phane, which is consumed as a delicacy. A study was conducted to determine the sanitary quality of phane and the kinds of microorganisms associated with it. It also looked into the potential for the existence of health risk associated with its consumption. Laboratory- and field-processed phane and that from open markets were subjected to microbiological analyses. The total microbial population for the larvae was in the range of 3 x 105 to 2 x 107 CFU/g. Species belonging to seven genera of bacteria and five genera of fungi were isolated from the larvae. About 50% of the identified bacteria were gram-positive, yet their combined population was much lower than that of the gram-negative bacteria. Cooking (89 to 93°C) under both sets of conditions (laboratory and field) reduced the microbial population to less than 9 X 103 CFU/g. The survivors were mostly sporeformers. Laboratory-processed phane was contaminated during drying, but none of the isolates were coliforms and the population increment was marginal. Field-processed phane, on the other hand, had a population of 4 x 104 to 1 x 108 CFU/g after 24 h of drying. The high moisture content of phane (55%) and a high degree of contamination from the soil and air appeared to have contributed to the increased population. Aspergilli including A. flavus and phycomycetes were frequently isolated from the samples. Coliforms were present in 30% and 50% of the phane processed in the field and in market phane, respectively. Escherichia coli and Klebsiella pneumoniae were found in 33% and 21%, respectively, of samples acquired from the market. The presence of K. pneumoniae, E. coli, a toxin-producing sporeformer (Bacillus cereus), and mycotoxin-producing fungi (A. flavus, Penicillium sp., and Fusarium sp.) all point to the possible existence of health risks associated with its consumption.