A woman accused of three murders by serving a toxic mushroom dish has admitted she foraged for the fungi and accepts there must have been death cap mushrooms inside a lunch she cooked for her former husband's family.

"In terms of the meal you cooked for the lunch, which is the subject of this trial, do you accept there must have been death cap mushrooms in that meal?" defence barrister Colin Mandy SC asked Patterson.

"Yes I do," she replied, shaking her head.

Patterson has pleaded not guilty to all charges and claims the poisonings were not deliberate, and the July 2023 lunch was a terrible accident.

The meal she served at her home led to the deaths of Don and Gail Patterson, 70, and Gail's sister Heather Wilkinson, 66, whose husband Ian was the sole surviving guest.

Wilkinson sat with his arms crossed as he watched Patterson give evidence on Tuesday about what went into the lunch.

She had lied to police about foraging for mushrooms, and about owning a food dehydrator, when she was interviewed, the jury was previously told.

Patterson told a jury of 14 she had begun wild mushroom picking when the COVID-19 pandemic threw Victorians into lockdown in 2020.

She had always enjoyed eating mushrooms because "they taste good and they're very healthy", she said.

"The first time I noticed them, I remember it was the dog eating some," Patterson, 50, told a Supreme Court jury on Tuesday, about finding wild mushrooms growing at her property.

"I picked all the mushrooms that I could see. I was trying to figure out what they were to see if they were a problem for him."

During her second day in the witness box in Morwell, in regional Victoria, Patterson admitted she developed an interest in picking wild mushrooms in early 2020, during the first COVID-19 pandemic lockdown.

She said when Victorians were allowed outside for an hour a day she would "force the children" to get away from their devices.

"For an hour or so, we would go to Korumburra Gardens for the rail trail and I first noticed them popping up then," she said.

"Have you always liked eating mushrooms?" her defence barrister Colin Mandy SC asked.

"Yeah, I had. They taste good and they're very healthy," Patterson said.

She said she would buy "all the different types that Woolies would sell" and would also purchase mushrooms from local farmers' markets and grocers.

"I'd use them in curries, or pasta dishes, or soup, spaghetti," Patterson said. "They just taste more interesting. There's more flavour."

But she said she discovered it was hard to figure out "what a mushroom is" when she began picking them.

"One species I was particularly worried about, I believe they were called Inocybe," Patterson said.

She would use Facebook groups for mushroom lovers to identify different types, including ones she found on her three acre property in Korumburra.

"I identified the ones that were growing in the paddocks where I had the animals, to a degree was confident of them," she said.

"There were field mushrooms and horse mushrooms in those paddocks."

Asked by her barrister about the process of consuming wild mushrooms, she said over several months she got to a point where she "was confident about what I thought they were".

"I cut a bit off one of the mushrooms, fried it up with some butter, ate it and then saw what happened," Patterson said. "They tasted good and I didn't get sick."

Patterson and her children ate the wild mushrooms she picked and she said she "chopped them up very, very small".

Earlier, Patterson grabbed a tissue and wiped her eyes as she apologised for sending Facebook messages to her online friends about her estranged husband Simon's family.

"I needed to vent, I needed to get my frustration off my chest and the choice was either to go into the paddock and tell the sheep or vent to these women," she said.

"I knew they would rally around me and I probably played up the emotion of it a bit to get that support."

She said she did not mean those words and she was "frustrated" with her estranged husband Simon at the time.

"It wasn't Don and Gail's fault. It wasn't the family's fault. It wasn't even entirely Simon's fault. I played a part in the issue too," she said.

Patterson has pleaded not guilty to three counts of murder over the deaths of Don and Gail Patterson and Gail's sister Heather Wilkinson, after serving them a toxic beef Wellington in July 2023.

The trial continues.