Frogs were found in a salad and noodles sold in Japan at a supermarket and udon store. The Mainichi Shimbun interviewed the people involved and experts to find out how the frogs got into the food and whether it's dangerous to eat them by mistake.
The first incident took place on May 11, when a customer who bought a salad at Ito-Yokado supermarket in Ueda, Nagano Prefecture, reported that the salad was contaminated with a frog.
On May 16, the manufacturer of the salad, daily Hayashiya Co., based in the prefectural city of Matsumoto, identified the creature as a 2 - to 4 - centimeter-long Japanese tree frog.
The local Public Health Center is investigating the incident, but the manufacturer thinks that the frog was mixed with lettuce or other vegetables and didn't get removed in the process of washing by machine or visually removing foreign objects. The company has boosted its countermeasures, such as increasing the number of workers in the foreign object removal process from one to three.
In a take-out product that was sold on May 21, a frog was found in a udon restaurant chain in Nagasaki Prefecture. The item is part of the brand's new Marugame Shake Udon line, which was released on May 16, and had just begun to gain popularity.
Marugame Udon Inc. conducted inspections at all of its suppliers' plants that handle raw vegetables, believing that the contamination occurred at a vegetable processing plant. On May 25, the company announced that it would discontinue sales of certain products, including the ones in question. It had earlier announced its decision to stop sales until May 25.
Why do frogs become a part of food in succession? Taisei Nishi, a keeper at KawaZoo in the Shizuoka Prefecture town of Kawazu, which breeds and exhibits more than 120 species of frogs, says May to June is the breeding season for frogs, when the number of small insects they feed on increases. It is also their most active time of the year.
The frogs also eat moths and other insects that congregate around streetlights at night. It may be that they were attracted to the window lights of a factory and somehow ended up inside the facility, he said.
Frogs and other insects are more likely to get into the lettuce leaves during the evening when the outside temperature decreases, according to a lettuce farmer in the northern Kanto region.
If a person touches the mucous membranes with hands that have touched a Japanese tree frog, it is toxic, causing skin irritations and rashes. Is it safe to eat a frog without being aware of the danger of eating a frog? If you eat raw meat, you could get sick, he said.