Caterpillar wriggling in nut bar hard to stomach

The Tasti Snack Bar. Photo / Greg Bowker

When Atul Awasthi bit into his muesli bar during his lunch break the last thing he was expecting was a caterpillar crawling out.

The Auckland scientist was on a lunch break from an animal pharmaceuticals company in East Tamaki when the caterpillar wriggled out between the chocolate-coated nuts on his Tasti nut bar.

Mr Awasthi immediately went to the toilet to throw up. "I was horrified."

Experts say the moths, which are commonly found in household pantries, are almost impossible to avoid and are not harmful to humans.

But Mr Awasthi feels that Tasti, which apologised and sent him vouchers for two free packets of the muesli bars, were "blase", and did not take his complaint seriously enough.

Tasti, a Te Atatu-based company which produces muesli bars and cereals, said it had done everything in its power to prevent the Indian meal moth from getting into stock. Marketing director Adrian Cook said the "nasty little creature" was a known worldwide problem.

The company had also received complaints about cereals in December but Mr Awasthi's was the first involving a nut bar.

No recalls had been issued on the nut bars because it "is quite a common sort of thing that happens and it's very isolated".

"We've done everything possible. We are not in any way blasé. It's a major issue that we have to deal with very seriously.

"The problem with the Indian meal moth is that it's very hard to know at what point the infestation occurs because they can eat out of packaging and they can eat into packaging."

He said the company was audited and checked for its health compliance and had passed all tests.

Rod Asher, an invertebrate taxonomist at Cawthron Institute in Nelson, said the Indian food moth was "extremely common".

"I would say it's nigh on impossible to keep out," Mr Asher said.

INDIAN MEAL MOTH

* Commonly found in household pantries.

* The adult moth lays eggs near a food source.

* The eggs hatch into caterpillars which munch their way through the food.

* While it is eating, it spins a thread which is sometimes left hanging in food.

* It then produces a thin silk-like cocoon before it becomes a moth.