Grilled eel sold in a department store in Japan has been found to be the culprit of about 130 food poisoning cases.

According to Kyodo News+, the store in question is Yokohama's Keikyu Department Store.

The Tokyo-based eel restaurant chain Nihonbashi Isesada sold more than 1,500 dishes of grilled eel and bento boxes of grilled eel and rice on Jul. 24 and 25 (Japan time).

This period, known as "Doyo no Ushi no Hi" ("Midsummer Day of the Ox"), is when Japanese may eat grilled eel in honour of an old belief that unagi can help them keep cool in the hot weather.

Bacteria in eel

Reports from a health centre yielded results from the testing of excrement of some of those who consumed the meals, which included eel in soy sauce and mirin rice wine.

They detected a bacteria called staphylococcus aureus, which can cause vomiting and diarrhoea.

Kyodo News+ also reported that the affected people displayed such symptoms, although most were not gravely affected.

One person, a woman in her 90s, did pass away. But the exact cause of her death is unknown.

Department store apologises

Shinji Kaneko, the president of department store, has since issued a formal apology.

Japanese news sites showed pictures of him in a deep bow and offering his condolences.

"We take what happened very seriously and feel deeply sorry about it. We will fully cooperate with investigations by public health authorities," he said.

Top images via Takuma Tsubaki/Unsplash