Tom Jamieson / New York Times News ServiceKalles Kaviar, a cod roe paste, is uniquely popular in Sweden. Kalles has never found much favor abroad, a fact that is now being used in gently mocking ads to help bolster the product’s Swedish identity.

Kalles Kaviar is Sweden’s answer to Marmite.

Made from cod roe, it is squeezed out of what looks like a bright blue toothpaste tube and should not be confused with fine Russian caviar. Swedes love it, but for the rest of us, it can be hard to swallow, unless a salty and fishy pinkish goo appeals to you.

And that’s the wry point of a long-running advertising campaign from Orkla, the Norwegian food company that owns the Kalles brand.

A commercial set in Los Angeles, which aired in Sweden during the World Cup last year, was typical. A kindly looking Swede in an apron stands behind a kiosk on the beach. He serves beachgoers bread topped with Kalles, or tries to.

“Excuse me, would you like some Kalles Kaviar?” he asks passers-by.

The Californians rebuff him, again and again.

One man emphatically shakes his head with a look of disgust. A woman waves him away.

An old surfer in a wet suit was blunt. “You don’t want to serve that to people, dude.”

At the end of the commercial, the hapless salesman sits next to a lifeguard stand as the sun recedes. He eats his pink goo alone on the beach, looking satisfied and at peace.

A tagline that closes the commercial says: “A very unique Swedish taste.”

Cecilia Sajland, marketing manager for Kalles, said, “We wanted to show other nationalities’ incomprehension when it comes to very Swedish tastes like Kalles,” adding, “We wanted Swedes to feel unique and proud of the brand and the taste.”

The recipe for Kalles was sold by a peddler to Abba Seafood, a defunct Swedish company, in the early 1950s, for 1,000 Swedish kronor, or less than $200 at the time. It was originally sold in plain tubes, according to an account on Orkla’s website. But the tubes were soon made over to feature Swedish colors — blue and yellow — and a picture of the son of the chief executive of Abba Seafood. The son, now grown up, receives a free lifetime supply.

The formula seemed to hit a sweet spot in a caviar-loving nation, and 1 million tubes sold in the first year. Orkla acquired Abba in 1995. Today, the company sells about 3,300 tons of Kalles a year.

Some people eat it on bread, some with cheese, but about 60 percent eat it with eggs, typically with slices of boiled egg, according to Orkla’s research.

“I suppose the U.S. equivalent would be peanut butter,” said Jonas Aurell, who along with his wife, Bronte, owns ScandiKitchen, a London cafe and marketplace that sells Scandinavian food, including Kalles.

Kalles’ omnipresence does not travel across the border to Norway, where Norwegians prefer other brands of caviar in a tube, particularly Mills Kaviar, which Aurell said had a stronger taste.

The Kalles commercials began in 2012 and were made by the Swedish ad firm Forsman & Bodenfors. If nothing else they are a whimsical cultural excursion into manners. While the Californians don’t hold back their feelings, a taste test in Switzerland yields more hand and eyebrow gestures than actual verbal responses.

The most expansive response comes from a serious-looking man in a tie.

“It tastes …” he says. “It tastes …”

“Fantastic?” a Swede asks.

“No,” the Swiss man replies, with a resolute firmness.

Farther east, in Budapest, the reaction is icier. A woman takes a bite, exchanges freighted glances with a friend. Asked if she likes it, she smiles, and says “yes,” with a look that clearly says no.

While Costa Ricans laugh and gesticulate, a woman in Tokyo bows, smiles and retreats while she appears to be gagging on a mouthful of Kalles.

“You sort of have to be born with it or grow up with it to appreciate the taste,” said Ann Spennare, who handles the Kalles account for Forsman & Bodenfors. “To eat a sandwich with Kalles Kaviar and an egg on it is something you long for if you haven’t been home for a long time.”