"We've all looked at the milk in the fridge and thought, 'Oh, the best before date is today. I'll throw that away', when, actually, it's perfectly fine to consume," says Jenny Marshall, who heads WasteMINZ Behaviour Change, a group addressing New Zealand's food waste problem.
Working with councils, the group is picking through individual rubbish bags to classify food scraps. The aim is to study the insides of 600 bags over the next three months to get a better picture of what, and how much, we're throwing out.
It's dirty work with humanitarian implications. The world has more than enough resources to feed every person comfortably, yet millions are malnourished and dying of starvation; 27 per cent of Kiwi children live in poverty.
Economically, food waste makes no sense, either. Then there are the environmental factors. If you throw out a banana, you're wasting the water, energy, land, labour and pesticide used to grow it, not to mention the greenhouse gas emissions produced to transport it here - and those it gives off once it's in landfill. If we're anything like the Aussies, we're throwing out about 20 per cent of the groceries we buy.
"It's a behavioural and cultural thing," says WasteMINZ CEO Paul Evans. "If you look at Singapore and Germany, they waste so much less food. In New Zealand, people don't like using their leftovers. They're not planning meals. They buy a whole lot of fresh fruit and vegetables with great intentions. Then they stick it in the cooler drawer and it ends up
getting tossed out."
So how to minimise food waste without compromising our health? Correctly interpreting food labels is a good place to start. "Use by" is simple enough, a definitive safety measure for highly perishable items: fresh and cooked meats, seafood and prepared salads. Unless it's frozen or you're Matthew McConaughey preparing for a film, it's best adhered to.
But products with a "best before" date relate to quality, rather than safety.
"Just because a product has passed its 'best before' date doesn't mean it's unfit for consumption," says Dr Miranda Mirosa, a food scientist and lecturer at the University of Otago. "It's probably perfectly safe to eat."
Biscuits, crackers, pasta, soft drinks and canned goods often come with these dates and are generally fine to consume weeks, months and sometimes years after the "best before", provided they've remained in their packaging and have been stored correctly. It's also reassuring to know the label is a conservative measure.
Manufacturers have to take into account all types of consumers, even those with a tendency to leave the milk and spinach sitting in the boot for five hours.
Even so, "best before" labels require a decision, and it's often a confusing one. Is the cream cheese a week past its "best before" going to make us violently ill?
"The majority of food-borne illnesses don't come from shelf-life issues but from contamination," says Dr Mirosa. "The pathogen has to be on the food for us to get sick. So it's less to do with how long you've had it around than how the food was handled."
In other words, if the cream cheese stayed in the fridge unopened, you're probably fine. Common sense prevails when consuming goods past their "best before", she says. Don't eat soft cheeses that have gone mouldy, for instance.
Yet it seems we've lost the confidence to trust our senses.
"In our grandparents' day there were no labels but people were more connected with food. People are becoming more interested, though, if you look at the popularity of farmers' markets and the slow food movement [an anti-fast-food philosophy that emphasises provenance and tradition]. We're relearning how to smell a piece of meat and look at the colour [to determine its freshness]."
Eatbydate.com, a website run by foodies who've set out to debunk the myths over products' shelf life, say that unopened, refrigerated cream cheese will last for 3-4 weeks past its "printed date". Opened cream cheese, however, lasts for 1-2 weeks in the fridge. Deli meats, if properly stored, can last for four days. Butter can last for three months. Frozen vegetables can last a year. As for those dried lentils, they'll last for an "indefinite" period (one to keep in the bunker, then).
But that huge variation in shelf life, and the lack of guidance (other than our senses) is probably not much help to a busy pregnant woman, who cannot risk getting listeria, yet can't remember how long the half-used cream cheese has been sitting there.
Adding to the confusion is the official advice from the Government's food standards website, which recommends "at risk" people - pregnant women, the elderly, etc, avoid eating things that are past their "best before", including refrigerated foods.
The kicker for the rest of us is that dates become irrelevant once food has been opened. At that point, we need to rely on the storage instructions and trust our noses. This is where I'd predict most of our food waste happens. Rarely will something remain unopened in my fridge but there is often a lot of partially used items - those are the things that get chucked away.
Again, it's about common sense but Dr Mirosa says the key to reducing waste is in planning meals. She also recommends turning older vegetables into soup, and if you don't think you can use something before it reaches its "use-by" date, then freezing it could preserve its life - anything from breads to meats, as long as they're consumed within 24 hours of defrosting. Eggs that are close to their "use-by" could be cooked and left for another couple of days in the fridge.
Then there's bread. Just to make things a little harder, it gets its very own label that tells us when it was baked. Great.
Auckland teacher and mother of three boys Karen Symons avoids food waste by virtue of the big appetites in her house. Having to feed three boys and her husband, she likes to look for cheaper options to fill up the family. If it's in a packet, a tin or it's frozen, she's not bothered if it's past the "best before". So she shops regularly at Reduced To Clear, a supermarket chain that sells discounted products nearing their "best before" dates - and, in some cases, beyond them.
In New Zealand, people don't like using their leftovers. They're not planning meals. They buy a whole lot of fresh fruit and vegetables with great intentions. Then they stick it in the cooler drawer and it ends up getting tossed out - Paul Evans. Photo / Thinkstock
There are 14 stores nationwide offering fresh, dry and frozen products, deleted lines, cancelled export orders, goods with damaged packaging and poorly performing new products.
Symons says she trusts the supermarket's quality control measures to monitor that what they're selling is still of good quality.
"If there's no dent or rust you can probably use tinned food for six months, even longer after the 'best before' date," she says. "I could get a trolley full of stuff at Reduced To Clear for $70 that at Countdown would cost me $200. If I see $1 dried pasta, that can't get old. So I'll get eight bags instead of the two I'd get elsewhere."
On a recent trip to the Glenfield store, I bought a packet of coconut cream with a "best before" of November 2013. It was a tad crystallised but tasted fine; of course, had it been an odd colour or smelled unpleasant, I wouldn't have used it. And sure, I didn't mention any of this to the friends I served it to for dessert. But we all survived.
Thankfully, manufacturers are coming to the party, working out how to keep food fresher longer; Fonterra's light-proof milk bottles are a start. British retailers Marks and Spencer and Tesco use an "It's Fresh!" strip in their strawberry and tomato packaging to remove ethylene, the gas that causes fruit to ripen, thereby extending its fridge life by two days.
Some British supermarkets are vacuum-sealing meat to increase its lifespan. And a researcher at Beijing University, in China, has devised a smart label, one of a new class of technologies called time-temperature indicators.
The small tags are made of gel and contain gold and silver nanorods, designed to change colour at the same rate that the food inside spoils, tracking the decline of freshness along the way.
Other waste prevention measures include smaller loaves of bread, baked beans with screw-top plastic lids rather than tins, split packages, re-sealable bags and better information on packaging, although you could argue that some of these have their own environmental drawbacks.
If you're really concerned about food waste, you could always become a freegan, those resourceful anti-consumerists who trawl through refuse for edible items. But if the thought of eating someone's discarded burger doesn't appeal, and you can't see yourself storing, composting or using leftovers in a tuna and pineapple cottage pie, planning your meals and creating a shopping list for only the food you need for that week's meals is a good start to reducing waste.
"Think of the starving children," my mother used to say, as I refused yet another brussels sprout.
