The bananas look just the same. One bunch promises to help third world farmers pay for their children to go to school. You can even swipe your smartphone on the label to find out more. The other bunch doesn't make any promises but is confusingly labelled Ethical Choice. It's also a dollar cheaper.
Across the aisle, a slightly motley collection of organic vegetables offers pesticide-free goodness for you and your family. Except the carrots cost $6.99 a kilo instead of $2.99 and the asparagus looks shrivelled.
The tug-of-war between your conscience and your wallet continues all the way round the supermarket. Is it safe to buy fish? Understocked snapper is supposed to be an ethical no-no but at $37.99 a kilo, it's not so hard to give up. Fortunately gurnard - near the top of the ecological rankings - is on special today at $22.99.
At least half the space on the egg shelf is now devoted to free range, organic and barn varieties.The rest are labelled "caged eggs" - a helpful reminder of the gruesome pictures of battery hens you've seen on TV.
A free range tray on special costs about 50 per cent more but you don't know what you are getting. Does free range really mean eggs from healthy hens pecking happily in an open yard? Or, as small producers claim, does it mean thousands of hens kept inside giant sheds now the big companies have picked up the brand?
Welcome to the battleground of ethical shopping, where the average consumer's good intentions can be shot down by a barrage of conflicting information or just a well-aimed scud missile on the price tag.
To test the cost of following your conscience at the supermarket, we tried a weekly food run for a family of five, comparing regular prices with their ethical alternatives across a range of issues - mainly organic, free range and Fairtrade - at New World in Mt Roskill.
The ethical shopping list cost $342 compared with $271 for the ordinary shopping trolley, a difference of $71 or 26 per cent. The biggest increases occurred in staple foods which most large households buy in bulk, such as milk, flour and sugar, which together cost an extra $22.64. Organic fruit and vegetables cost $13.60 more, mainly because of one good deal on strawberries. This turned out to be a common problem. All through the store, ethical shoppers tended to miss out on specials, which make a big difference to the final cost.
Yet there was no shortage of options for those willing to spend the extra money. Most canned products had organic alternatives and it was hard to miss the Fairtrade stickers and free range eggs, pork and chicken.
As even the biggest sceptics admit, ethical consumerism is leaving its hippy, sandal-wearing image behind and going mainstream. One in four bananas sold in British supermarkets is now Fairtrade. Coles supermarkets in Australia are phasing out home brand eggs from caged hens and pork from producers who use sow stalls (cages barely bigger than the pigs).
New Zealand supermarket operators say the market for ethical products here is small but gradually increasing.
Foodstuffs' Auckland retail general manager Rob Chemaly says free range eggs now make up 15 per cent of sales at its Pak'n'Save, New World and Four Square stores and free range pork has become more popular since the sow stalls campaign.
In response to customer demand, the company's Pams brand of tuna is no longer caught with Fish Aggregation Devices, which lure large schools of fish to one spot and then scoop up everything in giant nets - killing turtles, sharks, juvenile fish and other wildlife in the process.
Progressive Enterprises, which owns Countdown, Foodtown and Woolworths supermarkets, says it started a home brand called Macro a year ago offering free range, organic and gluten-free products.
Spokesman Luke Schepen says sales of the brand's free range chicken, which can cost about $5 a kilo more, have grown steadily "which suggests customers are buying the product for reasons other than price - whether it's an ethical choice or one of taste".
The ethical consumer movement officially began in 1989 with the launch of a British magazine bearing its name. From 1999 to 2010 the market grew from 3 per cent to 9 per cent of all consumer spending in Britain, according to the Co-operative Bank's Ethical Consumerism Report.
New Zealand doesn't measure domestic sales in the same way but the overseas potential for more broadly defined ethical spending has caught the attention of exporters. A 2008 report by Moxie Design Group and NZ Trade and Enterprise puts the local market for Lifestyles of Health and Sustainability (Lohas) shoppers at $2 billion, based on a global estimate of US$550 billion ($720 billion).
The report says Lohas consumers make decisions based on deep-seated individual, social and environmental values, ranging from healthy eating to saving the planet. "They are making a conscious decision to live differently, review and restructure their lives based on what is important and meaningful. They don't consider themselves as 'greens' and prefer to see themselves as mainstream consumers trying to make better decisions at a practical day to day level."
Food campaigner and former Green MP Sue Kedgley says the fact ethical products are now everywhere on supermarket shelves shows the market is changing but the amount is still up to shoppers.
"Vote with your wallet, vote with your fork. Whenever you buy something you can be sending a message to food producers about the sort of food you want to buy."
She says some inner city supermarkets have gone totally free range in response to demand, which stems from greater awareness following televised pictures of suffering hens and pigs in the last two years.
The strength of this informed push is still a matter of debate. Last July almost half of consumers said they ranked ethical and green factors above saving money, in an online survey commissioned by the New Zealand Council for Sustainable Development.
But when shoppers were asked to choose just one factor, the rankings reversed. Price jumped from fourth to top place at 45 per cent and buying local was a distant second on 12 per cent.
That's not surprising, according to Professor Timothy Devinney, author of The Myth of the Ethical Consumer. The Sydney-based American marketing specialist says most so-called evidence of demand for ethical products is shonky because "all too often, survey radicals can turn into economic conservatives at the checkout".
He says overestimating the ethical market has hurt some businesses, such as US giant Walmart, which briefly tried organic food and clothing with poor results.
Devinney and his colleagues tested consumers in eight countries with ethical dilemmas about their buying choices and compared the answers with their buying history.
They found people were well aware of issues such as sweatshop labour and poor environmental practices but thought the Government, companies or legal-business system should change, rather than them.
The researchers also found an "astounding reluctance" to consider ethical issues above price and quality. Even the colour of a running shoe mattered more to most people than the conditions under which it was made.
Some may find it heresy, he argues, but regardless of the moral merits, cost matters more for most ordinary people.
Consumer magazine research writer Jessica Wilson says shoppers may choose the cheapest product because they don't have reliable information on a company's environmental record or ingredient sourcing as they stand in the supermarket.
Under time pressure, price wins the day, she suggests. "It is often the only hard and fast information you have in front of you."
Wilson says many shoppers want to know more about what's in their food and how it has been produced. "What consumers have a problem with is a proliferation of claims and they can become a bit wary - how can you tell which are genuine and which aren't?" Her organisation advises shoppers to ignore meaningless words like sustainable and environmentally friendly and look for hard evidence, preferably from independent certification labels.
She thinks some people will pay extra for ethical choices, as long as they are sure about what they're getting.
"They may be willing to put their money behind a product that stands up and is consistent with their own ethical world view. The problem would be if they were being charged that premium and on closer inspection, the producer was making claims that didn't really stack up."
Wilson says one of the biggest problems is inadequate food labels, which are the main source of information for most people. A survey in September said 58 per cent of shoppers found them difficult to understand.
Kedgley, who has led consumer education tours around supermarkets for years, strongly agrees.
"The only people I have ever met who can understand a nutrition label are nutritionists or dietitians. No average consumer can figure out the nutrition label at all. It's a waste of time.
Both women favour a simple advisory system like traffic light labelling, which gives each food item a series of green, orange or red lights for its level of fat, saturated fat, sugar and sodium. Last month food ministers in New Zealand and Australia rejected this but are considering similar alternatives, such as the star ratings used on fridges and washing machines.
Devinney argues giving shoppers more information won't help because only a minority are interested. He cites a US study which showed shoppers bought different products when they could see the unit prices, such as cost per 100 grams. When researchers tried to repeat the experiment with nutritional information, most shoppers ignored it.
He admits a traffic light-type system probably would change behaviour because it's so simple that shoppers could react without thinking. But he's concerned at the potentially arbitrary distinction between "good" and "bad" foods and the unintended health consequences that may follow.
Food and Grocery Council chief executive Katherine Rich agrees, saying a "bad" list using set limits of sugar, fat and salt could include foods which form part of a balanced diet, such as whole milk, cheese, marmite and honey.
She is amused to hear Devinney's analysis of the divide between good intentions and actual buying behaviour, saying it matches her own experience.
"If you stand in a store and actually watch people do their shopping, very few read labels at all. We're asking a little square of packet real estate to somehow solve the nation's obesity problems.
"But that said, we understand that there are some consumers who want to know more about what's in their food and that's why there's already a huge amount of information as well."
In some ways, says Rich, the ethical movement is the victim of its own success. It has managed to move issues from niche to mainstream - she lists the chemical formulation of laundry powder, detergent and shampoo and the widespread consumer rejection of bisphenol A (BPA) in baby bottles - but this makes it harder for the original innovators to stand out.
"A lot of issues relating to sustainability and ethical production end up becoming the norm and the ticket to getting on the shelf in the first place."
Rich argues that manufacturers and supermarkets also have to assess the difference between a real shift in consumer attitudes and background noise from campaigners.
She says New Zealand companies have been very slow to use genetically modified ingredients because of popular distaste for the idea, rather than scientific evidence.
"But there's always a judgment call because if you took every product off the shelf the moment a group somewhere made a complaint about it, there'd be very little left."
She's not surprised at the costs of the Weekend Herald ethical shopping basket, saying the price difference in free range eggs is still a deal-breaker for most shoppers.
She suggests organic fruit and vegetables may struggle because of the high quality of regular (and cheaper) local produce.
Kedgley says these cheaper prices are misleading.
"As a society we are all paying a cost for cheap, industrial food, whether it's in ill health, cleaning up our waterways, the spread of antibiotic resistance - these are all huge consequences of unsustainable industrial agriculture."
She urges shoppers who disapprove of animal cruelty to pay extra for free range eggs - "it's an ethical choice" - but concedes it's not always easy, even in the greenest of families.
"My son mentioned that. When they started in their flat, they were off buying free range eggs but after a few months they were back to the old... when you're trying to watch every penny, it's very hard."
Find out more about the issues in the Herald this week
Monday: Healthy choices
Wednesday: Free range
Friday: Saving the planet