What's the world coming to when an iconic Aussie grocery staple like Sunbeam sultanas has a line that says: Made from Australian and imported ingredients?

My romantic notion - fed by distant memories of school geography lessons and pictures of actual sun beams turning Aussie grapes into sultanas on massive drying racks in the Murray River "fruit bowl" - was dashed.

Who knows where those imported sultanas came from?

Now I'm in favour of free trade, up to a point. I could reluctantly understand the restructure of uncompetitive industries like clothing and footwear that sent them off-shore - sad as it was for the individuals who lost their jobs.

And I admit I, like many Australians, have an imported car.

But somehow food seems different. Food production is the very basis of human existence, and it just doesn't seem right that we "outsource" so much of ours when Australia is a bountiful country, capable of producing food of the highest quality.

How does it make economic, environmental or social sense to ship food halfway around the world to undercut Australian produce, especially when much of it comes from countries that struggle to feed their own people?

The big supermarket chains are major contributors to this problem, flooding their shelves with cheap imports at the expense of familiar Australian brands.

Recently the consumer magazine CHOICE released the results of a survey of 360 supermarket home label products that showed just 58 per cent of Woolworths' and 55 per cent of Coles' own-brand groceries were produced locally. The supermarkets disputed this, but a simple browse of their shelves will show you how much of their processed foods are imported.

While it is hard to feel sorry for Coles and Woolies, the reality is that their focus on cheap imports has been sharpened by competition from German low-cost supermarket chain Aldi.

In May, entrepreneur Dick Smith made a detailed submission to a Senate inquiry into the food processing sector, in which he said the arrival of Aldi had led to more food being imported from lower-cost countries and greater pressure among supermarket chains to lower prices.

Smith said this was "causing the gradual decline in the Australian food processing sector to the point where some sectors have disappeared completely".

And if they haven't disappeared, chances are they have been bought by overseas interests.

As it happens, Sunbeam is now controlled by Chinese interests while other Aussie grocery icons like Arnott's Biscuits, Golden Circle, Edgell and Masterfoods are owned by US or UK companies.

But at least they mainly use Australian ingredients, or at least I thought they did. But these days it is getting harder to tell by reading the labels, which can be misleading to say the least.

The Australian Greens have introduced a proposal to Federal Parliament seeking more clarity in Australian "country of origin" food labelling, but strangely they haven't received much support from Labor or the Coalition. Quite the opposite, in fact.

It just doesn't make sense. Why don't our politicians want shoppers to be able to make better-informed choices about where their food is produced?

Nick Hartgerink is a former Mercury editor who now runs his own media consultancy.