The authorities say that 78 people were hospitalised after eating the meat, which is considered a delicacy in Zanzibar.
Eight children and a woman have died after eating sea turtle meat in the Zanzibar archipelago.
The authorities said that 78 people were hospitalised after eating the meal on Pemba Island. It is considered a delicacy in Zanzibar.
Eating contaminated sea turtles can cause chelonitoxism, a rare type of food poisoning that can be lethal. There is no known antidote and only supportive treatment can be offered to patients.
Haji Bakari, Mkoani District medical officer, said that laboratory tests show all those affected had eaten the turtle meat on Tuesday.
He added the adult who died on Friday was the mother of one of the children who died earlier in the week.
The authorities in Zanzibar, a semi-autonomous region of Tanzania, sent a disaster management team led by Hamza Hassan Juma to the island. He urged people to avoid consuming the animals.