Food labels needs to be clearer so consumers know where their food comes from and where it was processed, an inquiry has heard.
Australians love buying Aussie food, but have trouble telling if what is on the supermarket shelf is, in fact, Australian.
A federal inquiry into country of origin food labels is grappling with the question of how to help consumers understand where their food came from, where it was processed and who processed it.
Australian Manufacturing Workers Union food secretary Tom Hale says when Heinz was making tomato sauce in Australia, its labelling said it was "made in Australia from local and imported products".
"It was predominantly from paste that was imported," Mr Hale said.
"But the labelling didn't reflect this."
Country of origin food labelling must be simple, the inquiry heard, but complex food production chains are hard to boil down to symbols and colours.
Australian Made spokesperson Ben Lazzaro said in the case of imported pork that is cured in Australia, the local producer cannot use the "Australian made" logo, but it can use the words "Australian made".
He says food labelling needs to be improved.
"The concern is it's going into our bodies - where does it come from?" he said.
In a hearing in Melbourne, inquiry chairman Rowan Ramsey MP said food products with a range of ingredients were difficult to label.
"It's pretty easy with a tin of canned tomatoes," Mr Ramsey said.
"But what of a meat pie? The pastry or the little bit of meat or the gravy - which one's the principal [ingredient]?"
One suggestion is that country of origin labelling could be based on the most significant ingredient by weight.
But this creates a problem for products like orange juice, the AMWU says.
When made from imported concentrate, the heaviest ingredient in orange juice is water.
"The major weight in that would be water, rather than the concentrate, which is really what makes the difference between orange juice and water," Mr Hale said.
"It's a very complex area."