"He was so upset about it that he wanted to apologise to the child in particular," she said. "He feels extremely badly about what happened."
However, the girl's father said in a statement outside of court that he had no sympathy for Sefton.
He said the incident had a lasting impact on his daughter.
"Not once has the offender reached out to our family to apologise," he said. "His lawyer came out and said the public shaming he has had through social media has had a big impact on his life.
"He's not the victim, the poor little 4-year-old girl who keeps bringing up the time someone threw 'yucky stuff all over me' is the victim.
"The dad who is now always conscious of where he parks the car and conscious of opening the door to let his children out, is the victim.
"Not some gutless guy who thinks throwing a whole container of coleslaw out of a moving vehicle smashing all over a 4-year-old girl and her father.
"For him to not offer one apology to our family just shows how gutless he really is.
"The container exploded on impact. People in their house over 100 metres away came over saying it sounded like a beer bottle had exploded.
"Shards of plastic and coleslaw smashed all over my 4-year-old daughter and myself. The container was almost unrecognisable.
"My wife thought we had been side swiped by a car. And he is upset about a public shaming on social media? Really?"
Sentencing Sefton at Maroochydore Magistrates Court in Australia, Magistrate Haydn Stjernqvist said he took into account Sefton's previously clean record, that the behaviour had been "out of character" and the effect of public shaming.
"This would be something you wouldn't be repeating in the future," Mr Stjernqvist said.
- Additional reporting Sunshine Coast Daily