Shares of Japanese packaged food producer Warabeya Nichiyo Holdings dropped as much as 8.6% on Monday, the most in ten months, after apologizing for the alleged discovery of a cockroach in one of their onigiri rice-balls.

Seven & i Holdings’s Japan subsidiary also published an apology. Its shares fell as much as 1.1% at the open before recovering to trade slightly higher and in line with the broader market.

Warabeya trimmed its loss to 4.5% at 11:30 a.m. in Tokyo. The company said it is recalling all relevant goods from the factory in Omiya where the food was produced, according to a press release.

The stock market action followed a video that went viral Friday with footage of a rice-ball that appeared to contain a cockroach at a Seven Eleven convenience store.

Warabeya mainly produces boxed lunches, ready-to-eat flavored rice-balls and snack pastries. Seven Eleven Japan contributes a majority of the companies total sales, according to company filings.

While Japan is widely known for its cleanliness, there have been a number of high-profile cases of food contamination over the years that have shocked the nation.

Earlier this year, conveyor-belt sushi restaurants were scrambling to control the narrative around the "sushi terrorism” phenomenon, in which customers recorded themselves committing unhygienic acts such as licking soy sauce containers and other communal items.