A potential methodology for differentiation of ciguatgoxin-carrying species of moray eel

A food poisoning incident due to ingestion of an unknown moray eel occurred in Taiwan. To identify the species of causative moray eel implicated in food poisoning, a 376-bp fragment sequence of cytochrome b gene was successfully obtained from four species of moray eel by using a pair of primers (L newest-1/H 15149). This fragment could be amplified using fish meat treated with different heating processes (100 °C for 30 min, 100 °C for 60 min, 121 °C for 15 min, and 121 °C for 30 min). After sequencing, it was found that no variation in sequence was detected among individuals within each species. The species of causative moray eel implicated in food poisoning was judged as Gymnothorax javanicus based on sequence analysis. In addition, using restriction enzyme analysis, including Taq I and Sau96 I, could distinguish these four species of moray eel and identify the fish species of poisoning sample as G. javanicus. The toxicity of viscera in 24 specimens of four moray eel species was not detected, but the food poisoning sample was found to be toxic. Overall, this study proved that DNA sequence and restriction enzyme analyses are useful in identifying that the causative moray eel species was G. javanicus.