Dodgy relish served at the Melbourne Cricket Ground is being blamed for nearly 40 people falling ill at an exclusive Anzac Day function.

Investigators spent months trying to recreate dodgy relish that gave nearly 40 people gastro at an exclusive Melbourne Cricket Ground luncheon on Anzac Day.

Thirty-seven patrons and a staff member were left distressed and light-headed, with some fainting and going to hospital, after eating the quince and fig jam relish with barberries at the Essendon Football Club's president lunch on April 25.

"It was a pretty dramatic foodborne outbreak,' Victoria's chief health officer, Brett Sutton, told reporters on Tuesday after a three-month investigation into the incident.

Rabbit, chicken and pork terrine served with the relish was initially suspected to be the culprit.

But after 109 interviews trawling through everything guests and staff members ate that day, the investigation found the relish was almost certainly to blame.

"In the fashion of a true foodborne mystery, it was the relish in the (MCG's) Olympic Room at high noon on Anzac Day," Dr Sutton said.

The investigation took three months in part because investigators were trying to recreate the relish under various conditions, but they were unsuccessful.

"Dehydrated barberries, barberries with boiling water, the relish refrigerated for three days, the relish left out, none of it allowed sufficient growth of bacteria that would have caused that illness,' Dr Sutton said.

"I suspect that something in that relish, barberries or the fig jam, carried a toxin at the time and the boiling water that was used in the processing wasn't sufficient to kill it."

Seven people were taking to hospital after being struck down by the gastro but none required admission.

AFL boss Gillon McLachlan and Governor Linda Dessau were among those at the event, but neither fell ill.

The Melbourne Cricket Club and catering partner Epicure say extra precautionary measures have been put in place since gastro outbreak.

The food from the function, during the Bombers' four-point AFL win over Collingwood, has not been served at the MCG since.

"We are deeply disappointed that this incident occurred and express our sincerest apologies to those patrons affected on ANZAC Day,' the MCC and Epicure said.