As the murder trial of ‘Mushroom Lady’ Erin Patterson enters its second week, it’s been the turn of expert witnesses to take the stand. Doctors, hospital staff and scientists have given evidence on everything from Erin Patterson’s own health following the fatal lunch to forensic investigations.
Earlier in the week, the court also heard from Patterson’s children, who testified about their parents’ relationship and what they did on the fatal day and after. The children gave evidence that on the day of the lunch, their mother, Erin, dropped them off in town to take in movies and fast food, telling them that she had ‘adult stuff’ to talk about with her lunch guests.
That ‘adult stuff’ referred to Patterson’s telling her guests that she had cancer and needed to know how to break it to the children. However, the medical evidence is that Patterson never had cancer. The prosecution alleges the false claim was a gambit to get the children clear of the fatal lunch.
However, the children later had some of the leftovers. Her son described it as the best meal he’d ever had. Naturally this raises questions about how they avoided the same mushroom poisoning. Erin Patterson claims she scraped the mushrooms from the portions served to her children, because they didn’t like them. Whether this would have spared the children from poisoning, if death cap mushrooms had been used (as we know they were) is a question for experts to resolve. It is known, though, that the amatoxins in death cap mushrooms are not destroyed by heat and can leach into the rest of a meal. Indeed, forensic testing found death cap mushroom toxins in samples of the meat.
The evidence shows that Erin Patterson in fact cooked multiple beef Wellingtons. When mushroom poisoning was first suspected, Senior Constable Adrian Martinez-Villalobos searched outdoor bins at the Patterson home and found “about 1½ beef Wellingtons” inside “a brown paper Woolworths bag”. Those were bagged and handed over to hospital staff.
While Erin Patterson’s children were unaffected, Patterson herself went to hospital after her guests had been admitted with serious poisoning symptoms and claimed to also be ill. Patterson later checked herself out, against the advice of doctors who had realised that the other guests were suffering potentially fatal symptoms (three did die), and also refused to bring her children to the hospital for testing.
Professor Andrew Bersten, an intensive care specialist, testified on Wednesday. He did not personally examine Patterson, but told the court he had examined her medical records, including those from during her time at Leongatha and Monash hospitals in late July and early August 2023.
He found that her presentation was consistent with someone having a diarrheal illness.
He said he had not been shown any evidence that showed she had suffered from toxic poisoning, or cancer, during this same time.
When examining the results of the accused woman’s fecal specimen taken on July 31, 2023, he found no pathogens were detected.
Bersten said the illness did not appear to be severe and there was “no other biochemical evidence of a liver injury”. He noted that point-of-care tests conducted on Patterson showed normal lactate levels, whereas her now-deceased father-in-law Don Patterson suffered from extremely high lactate levels following his poisoning. Erin Patterson also showed normal urea levels, creatinine levels at the upper end of the reference level and slightly high haemoglobin levels.
Toxicologist Dr Laura Muldoon examined Patterson on the day and suspected gastro.
“She had some chapped lips but otherwise looked clinically well. No signs of Amanita poisoning,” Muldoon said.
Muldoon also said that Patterson told her she had bought mushrooms, which “might have been dried shiitake or porcini”, from an unnamed Asian grocery in Melbourne. Dr Conor McDermott, working as toxicology registrar at Melbourne’s Austin Hospital, where the critical victims were treated, also asked Patterson where the mushrooms came from. She said they were “button mushrooms in ... packaging from Leongatha Safeway”, and that she had also been to a Chinese food store in the Melbourne suburb of Oakleigh.
McDermott said he went on to do a Google search for Chinese food stores in the Oakleigh area and offered to read the names out to Erin in an attempt to track down the seller. “She said she would not be able to remember,” McDermott said.
Dr Chris Webster, who treated Patterson for her gastro systems at Leongatha Hospital, also asked about the source of the mushrooms.
Webster said Erin gave him a short response. “Single word answer: ‘Woolworths’,” Webster told the jury.
Patterson also told Dr Rhonda Stuart, the medical director of infection prevention and epidemiology at Monash Health, that she hadn’t foraged for mushrooms. Dr Stuart said Patterson told her the dried mushrooms had a strong smell. Another mushroom expert, Dr Tom May, told the court that there was no distinct smell from fresh-picked death cap, but they emanate a strong smell when dried.
Mycologist Camille Truong, a fungi expert from Melbourne’s Royal Botanic Gardens, was asked to test the leftover beef Wellingtons.
She told the jury the only mushrooms she could identify were field mushrooms, typically found in supermarkets.
“I was told all the mushrooms were coming from … a shop or supermarket. No foraging activity,” she said.
Further forensic testing, by forensic toxicologist Dimitri Gerostamoulos, found death cap mushroom toxins in the mushroom paste and meat.
Toxins from death cap mushrooms (beta amanitins) were found in some mushroom paste and a meat sample taken from the meal.
Professor Gerostamoulos said he undertook “an analysis at much lower levels than what the naked eye can detect or identify”.
“We rely on sensitive instruments to be able to detect very low quantities,” he said, adding he would be able to identify the toxins even if mushrooms had been blitzed to a powder.
Death cap mushroom toxins were detected in four samples of vegetable debris taken from Erin Patterson‘s food dehydrator, the court has heard.
In yet another twist in the case, a juror has been discharged for misconduct.
Victorian Supreme Court judge Christopher Beale on Thursday told the jury he had received information the juror may have been discussing the case with external parties “contrary to my instructions”.
The trial began with 15 jurors, now down to 14. Of those, 12 will be selected by ballot to deliver the final verdict.
