Earlier this week it was reported the stomach bug was related to consumption of packaged carrots and lettuces, however this was yet to be confirmed.
Some foods have been consumed by a significant proportion of those who have become ill, however they are foods that are also regularly consumed by people who are not ill, MPI said.
There is no single food that has been consumed by 100 per cent of those who have fallen ill with the bug, the ministry said.
Advice for consumers
MPI advised consumers to beware of stomach cramps, which may mimic appendicitis.
Diarrhoea can occur but was rare, and the bug has a incubation period of three to 21 days, MPI said.
Consumers were also encouraged to apply normal food practice.
MPI said if food looked or smelled off it should be thrown out, otherwise fresh food should be chilled and fruit and vegetables washed before eating.