/jp/ - Otaku Culture

Okay, time for another short mystery!

It's an alternative version of the First Game. The family have just discovered the 6 bodies in the garden shed. They're sitting in the lounge, discussing what to do.
In the meantime, Gohda and Kumasawa are in the kitchen preparing food, accompanied by Nanjo and Genji. On Natsuhi's advice, they only get tinned food because she fears the murderer might have poisoned the food.
Eventually everyone on the island is gathered in the lounge and eating their food. After a very short time, Natsuhi suddenly stands up and mumbles something about a terrible headache and wanting to lie down in her room. She takes a couple of wobbly steps and falls down right after opening the door. The family and servants are all shocked and Nanjo is on the scene quickly. He checks her pulse and soon declares her dead by cyanide poisoning. However.

/RED/ Everyone in the lounge had the same exact food as Natsuhi.
/RED/ Natsuhi definitely died because of cyanide poisoning.
How come only Natsuhi died of cyanide poisoning?