Gisborne cockroach and a corpse loving ‘coffin fly’ identified in Whangārei man’s supermarket cheese

Onerahi pensioner Ian Score's cheese is still under investigation by MPI. Photo / Michael Cunningham.

Food safety officials are still investigating how two insects got into a block of supermarket cheese, purchased in Whangarei.

Shopper Ian Score bought the 1kg pack of Woolworths Everyday Cheese from the chain’s Okara Park store in March and reported finding the bugs to the Ministry for Primary Industries (MPI).

Score said he received an update this week from MPI, which wouldn’t tell him much about its investigation so far other than the two bugs were different types of insects – not both cockroaches as he first speculated.

The larger of the two bugs, which he noticed embedded in the top of the cheese when he opened the pack, was a Gisborne cockroach. Another smaller creature, embedded further down the block, in an unopened part of the wrapper, was a scuttle fly, a nickname for the phorid fly, which is also known as a ‘coffin fly’.

A Gisborne cockroach, which Ian Score found in a block of Woolworths Everyday cheese he bought from the supermarket's Okara Park store, in Whangārei. Photo / Michael Cunningham

This second, smaller, insect, embedded further down an unopened part of the block, has since identified by the Ministry for Primary Industries as a scuttle fly. Photo / Michael Cunningham.

The Advocate approached MPI but it declined to comment while its investigation was “ongoing”.

According to the online site of Arrow Exterminators, ‘scuttle fly’ is one of many nicknames for phorid flies.

The nickname “scuttle flies” comes from their habit of running rapidly across a surface when disturbed, rather than taking flight.

They are also called “coffin flies” because they favour decaying, moist organic material as both a source of food and for laying eggs.

They are found near corpses and are sometimes used by the forensic community to help estimate a person’s time of death or when a burial occurred.

Phorid flies may be easily mistaken for fruit flies or drain flies. Their life cycle varies from 14 days to 37 days, but adult phorid flies only live one week.

They eat a variety of decaying matter, especially organic material that gathers in drains or other plumbing. This includes decomposing food, fungi, and insects.

Certain species of phorid flies are also used as biological control agents of fire ants.