Viability of Dicrocoelium dendriticum metacercariae in Formica polyctena ants after exposure to different treatments

Abstract

In the western world edible insects have gained increased recognition for their taste, nutritional value, and potential for commercial-scale production of foods for human consumption and animal feed. The presence of food-borne parasites in insects is therefore a concern due to the potential hazards it may cause consumers. In this study we developed a viability assay including trypsin treatment of trematode Dicrocoelium dendriticum metacercariae from the abdomen of the red wood ant Formica polyctena. Then we tested the viability of D. dendriticum metacecariae in relation to: (1) freezing (-20 and -80 °C); (2) boiling (100 °C); and (3) ethanol (50%). The metacercariae in all controlants were alive and displayed movements either in the cyst, or after excystation, whereas all metacercariae from all treatment groups were recorded as dead. Freezing at -20 or -80 °C for 30 min, boiling for 1 min or storage in 50% ethanol for 24 h proved effective in killing the lancet liver fluke D. dendriticum metacercariae.