The conflict began shortly after the renowned Latvian conductor Andris Nelsons brought the bombastic introduction to the fourth movement to a shuddering halt, leading his Leipzig Gewandhaus Orchestra deftly into the movement's slow, atmospheric adagietto, wrote the Sydsvenskan newspaper.
At this point that the rustling on the second balcony became apparent, ruining the effect of the gently soaring strings and softly plucked harp for all sitting nearby.
After a few minutes, a young man sitting next to the woman with the chewing gum lost patience, snatched the bag from her hands and threw it to the floor.
A witness told the Sydsvenskan that the woman had appeared chastened, sitting in silence throughout the rest of the 70-minute romantic epic, the performance of which has been likened to climbing Mount Everest.
The moment the music stopped, however, she took her revenge.
“When the applause broke out, the woman turned towards the man and said something,” Britt Aspenlind, who was sitting two rows behind the pair, told the newspaper. “The woman gave the younger man a slap right in his face. He became angry and started fighting back.”
Another witness said that the blow had been powerful enough to knock the man's glasses from his face. The woman's companion, an older man, then seized him by his shirt, and began to throw punches in his direction.
Olof Jönsson, who was sitting in the row behind, described the onslaught as “a violent attack”. “It was very unpleasant actually. I've never seen anything like it,” he told Sydsvenskan.
Eventually, the other audience members managed to calm the two sides down and they went home.
After news of the brawl was published in Sydsvenskan, the concert venue Malmö Live posted a light-hearted list of concert etiquette.
“Everyone thinks it is wonderful to sit at a hockey or football match and drink a beer or coffee and eat little snacks…” it said. “In a concert hall with world class acoustics it is not however suitable to bring rustling bags of crisps.”
Anna-Maria Havskogen, the venue's communication chief, said she had felt that this was a rare moment when the venue could bring such matters to the public's attention.
“We seized the opportunity and felt that it was a good situation to write something up about etiquette and correct behaviour,” she said. “Normally we have no such misbehaviour, you could say, but we realized the news value.”
Asked whether the venue had other concerts planned which might be considered high risk, Havskogen initially said there were none, before following up with a text message sent to the newspaper.
“Possibly Verdi's Requiem on November 1st and 2nd could be a high-risk concert actually,” she wrote. “Extremely powerful, will awaken strong feelings….”