Japan's farm minister resigned on Friday because of a scandal involving tainted rice fed to hospital patients and schoolchildren, the latest in a string of food scares undermining public trust among Japanese consumers.
Seiichi Ota was appointed just last month and also faced reports of financial irregularities, but has denied any wrongdoing.
He is the fourth farm minister to step down in two years, with his predecessors all caught up in expenses scandals. One committed suicide after being questioned in parliament.
The food scandal, in which small companies sold rice contaminated with pesticides and mould to food and liquor companies, comes as the ruling party gears up for a general election that media have reported could take place as early as next month.
Japan's ruling Liberal Democratic Party is expected to vote for a new leader on Monday after Prime Minister Yasuo Fukuda quit abruptly this month.