Article published on the 2008-09-19 Latest update 2008-09-19 14:30 TU
Ota submitted his resignation to Prime Minister Yasuo Fukuda, who himself is due to bow out in a few days time because of a government crisis.
The scandal emerged earlier this month when Osaka-based company Mikasa Foods admitted selling the rice to snack-makers and telling employees to go ahead with the sales.
It has now emerged that more than 300 companies, including brewers, food ingredient wholesalers and sweet makers, used it. That means that tainted products have been served to children and the elderly, in shops, hospitals and schools.
The rice was imported from China, south-east Asia and America after a hotly contested agreement to open up the local market.
It was found to contain excessive levels of toxins, or be infected by fungi, or affected by other factors in storage. The govenrment sold it to private dealers on condition that it be used for industrial purposes, such as making glue, but it has found its way into the food chain.
Tokyo correspondent Julian Ryall says that the scandal has rocked many Japanese people's faith in the authorities.
"The Japanese pride themselves on the quality of the food that they are served in restaurants, in the food that they buy in their supermarkets," he told RFI. "The average Japanese housewife is absolutely shocked that they’ve been eating this and that they have been allowed to eat this by the authorities."
Ota, who last month declared that Japanese consumers are too "fussy" about food safety, announced his resignation on Friday, because of the "the large social impact that the tainted rice has had".