A Spanish craze encouraging single people to seek partners in supermarkets by using a fruit-based code has caused some chaotic scenes and even led to the police being called to restore order.

In recent days, many single Spaniards have been drawn to branches of supermarket chain Mercadona between 7pm-8pm by claims they can find romance at that time, particularly if they put a pineapple upside down in their shopping trolley.

The phenomenon seems to have been driven in great part by the actor and humourist Vivy Lin, who posted a video on TikTok of her pushing a trolley around a Mercadona store talking about the supposed window.

“The time to hook up in Mercadona is 7pm to 8pm,” she said.

On its official TikTok account, the supermarket posted a pineapple with the caption: “The pineapple on the shelf of Mercadona waiting for you to get a date.”

The pineapple manoeuvre is reportedly completed by pushing your trolley into the wine section of the store and hoping that a person you find attractive responds positively.

As the story has gone viral, it has led to some unusual and sometimes disorderly sights.

In Madrid there have been reports of groups of teenagers pushing trolleys around stores in the evening, without buying products.

One man was dressed as a giant pineapple by his friends inside a store as part of his bachelor party celebrations.

In Bilbao, police were called to a branch of Mercadona during the 7pm-8pm time slot because of rowdy scenes inside, although they were not required to intervene.

A song, circulating online, has further driven the success of the trend, with the words: “In the wine section / My heart races / Looking for someone special / That my soul needs.”

It is not the first time an upside-down pineapple has been used as a code. More traditionally, it has been used to allow people interested in swapping sexual partners, known as swinging, to find each other.

While the latest use of the fruit may have proved popular with some, there have been reports that the pineapple mania has not found favour with many Mercadona employees who are left to clear up unpurchased goods.

One video showed a worker pushing boxes of the fruit away from shelves and towards a storeroom as 7pm approached.

The company says the trend was “not launched by us, it has come about spontaneously”.

Some observers have taken a critical view.

“Falling into the clutches of a campaign designed through social media may be innocent, as is the case with ‘Pineapple-gate’, with all the jokes and childishness that it generates,” wrote social commentator Susana Quadrado in La Vanguardia newspaper.

But she warned it also showed how the virtual world “can condition social behaviour and turn users into loudspeakers for free”.