It is a habit which has p' />
Confusion over "best before" labels is contributing to Kiwis needlessly dumping uneaten food worth $750 million a year.
It is a habit which has prompted plans to remove the labels in Britain.
There, they are blamed for contributing to £6 billion ($12.26 billion) of food waste annually.
A top Australian economist, whose research reveals the wasteful habits of New Zealand households, says consumers need more context on the health risks of particular foods.
And he says reducing avoidable food waste could save households hundreds of dollars and reduce greenhouse gas emissions.
Britain is expected to introduce guidelines to better inform shoppers and make them more reluctant to throw out food which is not spoiled.
Government ministers blame "best before" and "sell by" dates for the wasteful dumping of food which could be safe and edible.
Instead of marking food as being "best before" a date, British retailers will have to produce labels giving details of the health risks associated with foods that remain on shelves for a long time before being eaten.
British households discard similar amounts of uneaten food to New Zealanders.
Economist Richard Denniss, executive director of the Australia Institute, said yesterday its survey of New Zealand households found each threw out about $450-worth of food a year.
This equates to a national figure of about $751 million of food being discarded annually.
Australians were chucking out food worth A$5.2 billion ($6.88 billion) each year - an average of A$616 ($815) for each household.
"Whether it's because it was off, or people just didn't like the look of it, we don't know," Dr Denniss said.
"We know best-before dates for some people are an indicator that they should be cautious, and for others they are a deadline they wouldn't possibly cross."
"Milk and yoghurt don't become poisonous the day after the best-before date. It's possible to put your nose in and determine whether they are still okay or not. We found younger people in particular, and also higher-income people, pay more attention to the best-before dates."
He said shoppers needed more information about the health consequences of food spoilage.
"The consequences of processed meat going off are quite different to the consequences of milk going sour."
In Britain, the proposed warnings will vary depending on the food type.
Seafood, or eggs would carry detailed warnings of food poisoning hazards; bread would have simpler labels because of its lower health risk.
University of Otago professor Richard Bremer, an expert on the shelf-life of food, says most shoppers do not distinguish between "best before" and "use by" dates.
He supported more detailed packaging, but warned that removing "best before" labels needed to be accompanied by consumer education.
"In the absence of education, people could just become a bit more paranoid and throw everything out."
New Zealand authorities say label changes are not in the pipeline.
Food Standards Australia New Zealand spokeswoman Lydia Buctmann said the independent transtasman review of food labelling, reported in January, did not propose any changes to the system of "best before" and "use by" dates.
"It is illegal to sell anything after the use-by, and you shouldn't consume it after that. The original intent was it be on foods that are risky after the date, perhaps a chilled lasagne.
"Best-before dates [foods] still are okay to sell and consume a little while after that date ..."
Information from the Ministry for the Environment showed that the most avoidable food wastes were potatoes, sliced bread, apples and meat.
Discouraging over-purchasing and needless disposal could also help reduce greenhouse gas emissions.
An Australian Institute report shows that food waste adds emissions from the products rotting in landfills, as well as from unnecessary farm production and transport.
Dr Denniss said: "There could hardly be a cheaper or more efficient way to reduce the pressure society places on the natural environment than to stop producing goods that will become a problem of waste disposal."
A "best before" date means the product's quality will reduce after that date. However, there is no immediate health risk, and it is not illegal to sell a product after its best-before date.
It is illegal to sell a product after a "use by" date. Supermarkets usually discount or dispose of products close to this date.