One of the first pictures to emerge on a social media site was of a young man lying on the ice creams in the freezer at the 24-hour store in Kochi prefecture where he worked. The image went viral and triggered a sharp intake of breath among older Japanese.
Days later, two secondary school students who worked part-time at a ramen noodle restaurant in Osaka upped the ante by posing with pictures of frozen ingredients used in the restaurant's dishes in their mouths.
The escalations continued and soon an employee of a pizza chain appeared on another social media site with a pizza base plastered across his face, while another youngster was snapped lounging amid a pile of hamburger buns at a fast-food restaurant.
The editorial writers at Japan's conservative Yomiuri newspaper were finally unable to contain their anger at the declining standards of a new generation of service-sector workers, describing the rash of pranks posted online as "deplorable".
"The young people who caused these problems seem to be exhibitionists who want to attract others' attention in cyberspace," the paper said in its August 30 editorial. "Some young people may want to show off to get others' attention, but the problem is how they go about it. If they had considered the consequences of their acts, the incidents would not have occurred."
The antics of a new generation of young workers, combined with the dangers of modern communications technology, triggered a wider outpouring of moral indignation in Japanese society which traditionally prides itself on politeness, respect for others and general common sense.
The owner of the store in which the member of staff climbed into the freezer lost his franchise with the parent company after it was inundated with complaints. Customers claimed the owner had failed to educate his staff and that it had poor standards of sanitation.
The two girls were fired from the Osaka ramen shop, whose owner had to close the restaurant for three days to dispose of the stock of frozen food and to sterilise the storage facilities.
The girls said they were only trying to be funny and did not think it was such a big problem.
"I don't think this is a problem of modern technology," said Makoto Watanabe, a communications and media lecturer at Hokkaido Bunkyo University.
"A wise person is able to use technology such as this wisely. This tells me that young people are losing the ability to regulate their behaviour and follow common social ethics.
"I think if they had talked with friends or family before they did something like this, then they would have been told quite clearly not to be so foolish."
Watanabe believed the breakdown in common sense can be traced back to a failure to instil discipline in young people in the modern Japanese family.
"These actions are a kind of performance or showing off," Watanabe said. "And now people can show off whatever they are doing on the internet straight away.
"When I was a kid, there were people I knew who misbehaved, but it never spread very far."
And Watanabe is concerned that despite the public's criticism and the Yomiuri editorial, other young people will see the photos and decide they want to do something even more outrageous.
"It could cause some to think twice about doing something else, but I think it is more likely to give a young person even more ideas about how to misbehave," he said.