In a society where cleanliness is revered, a series of pictures showing unhygienic pranks involving food industry workers and customers has triggered a media storm after going viral on social-networking services.

The posts reflect a broader trend among young Japanese Internet users for sharing reckless exploits online, which some observers believe has the potential to harm their future prospects.

The first of the images to gain nationwide attention was posted on Facebook in mid-July by a clerk in an outlet in Kochi of major convenience store chain Lawson Inc. in which a man could be seen lying inside a large refrigerator for ice cream.

In a Twitter post Aug. 18, a part-time worker at a Pizza Hut outlet in Tokyo was pictured wearing pizza dough on his face like a mask, causing Kentucky Fried Chicken Japan Ltd., which manages the chain, to formally apologize on its website.

The company said it had imposed a “severe punishment” on the worker, a university student, although it didn’t disclose the details, taking into account the “person’s future.”

These incidents, dubbed “baito tero” by combining the Japanese term for a part-time worker and an abbreviation for terrorism, have sparked a strong reaction from many Internet users.

After newspaper and TV reports, companies linked to such cases have disposed of large quantities of goods, with some even going to the extreme of closing outlets.

Meanwhile, a Twitter post Aug. 25 showing a young male making a “victory” sign while standing atop a police car led to the arrest of two teenagers involved. The Hokkaido Prefectural Police judged it was necessary to detain them to “prevent recurrence of similar crimes,” an official said.

Police in Kyoto and Oita prefectures turned over to prosecutors cases against teenagers who entered refrigerators for ice cream in shops and uploaded photos showing their conduct on social media.

Chinese restaurant chain Ohsho Food Service Corp. lodged a complaint against 10 customers involved in a picture, posted online, showing some of them stripped naked in an outlet in Kanazawa, Ishikawa Prefecture.

The Kyoto-based company decided to close the shop, saying it was “unacceptable to continue its service” because it could cause “customers to feel discomfort.” It is considering seeking compensation.

“With the widespread use of broadband and smartphones, people fooling around can easily post things on the Internet and social-networking sites, fueling the trend,” said Junichiro Nakagawa, editor of an online news site.

“Another reason is that it seems the number of people acting the fool is increasing because more and more people are trying to find these posts. I know there were some in the past that involved confessions of drunken driving,” said Nakagawa, who published the book “Net no Baka,” or fools on the Internet, in July through Shinchosha Publishing Co.

Some Internet users searching for such posts know there can be negative consequences for the people involved if the content goes viral. They may be motivated by a somewhat unusual sense of justice, according to Nakagawa.

Once targeted, personal information of a poster on the Internet is often easily found and exposed. Those who have their real names linked to posts showing reckless behavior could find their infamy hard to live down.

“It could harm their ability to find or change jobs, or even their marriage prospects,” Nakagawa said.

Nakagawa said some posters engaged in extreme conduct in an effort to gain a greater following for their accounts on Twitter or Facebook.

“People who carry out conduct of this kind are exhibitionists” and want widespread attention, said Tatsuhiro Yonekura, professor of information science at Ibaraki University. “If they want to show (pictures) among friends, they have only to resort to mail.”

According to Yonekura, the emphasis Japanese society puts on social responsibility, as well as its excessive demand for cleanliness, are behind shops being forced to shut down after gaining notoriety through the online posts.

As for countermeasures, Yonekura said: “Social rules and morals are far behind the progress of technology. It is necessary to develop media literacy and, of course, education is important.

“The younger, the better. Children should be taught the difference between what is happening in the Internet space and reality.”

KEYWORDS SNS, photo, prank