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Do you buy free range or Blue Tick eggs or go for the cheapest caged varieties?
Do you take your own bags to the supermarket or come out with half a dozen plastic bags? Do you know where your food comes from, how it was produced or what's in it?
Growing numbers of us are asking these questions whenever we shop, and choosing products that are sustainable, according to Dr Barry Law of the Christchurch-based Sustainability Company (NZ) Limited.
He is one of several speakers on the topic of food and sustainability at the New Zealand Guild of Food Writers' Conference in Dunedin this weekend.
Food and its production - and the numerous scandals and problems concerning food, from mad cow disease or horse meat masquerading as beef in the UK to Fonterra's contaminated milk scare here - have altered people's perceptions about sustainability and the importance of what's in their food, he says.
However, people get confused around the notion of sustainability.
It's more than just about the environment; it's about society and the economy and compliance and regulation as well, Dr Law says.
''We are seeing the rise of the socially conscious consumer who is demanding more information about where things come from, what is actually in the food and what impact it will have on their health.
''My view is that one of the leading contributors to more understanding around food is young women, especially young women with babies because they have become a lot more concerned.
"I think young people and the impact of social media - if they get a hamburger with a toenail in it they'll tweet it and put it out there immediately.
''You only have to look at what happened with Fonterra with the milk powder; what happened to Cadbury over palm oil and the size of the chocolate; you only have to look at what happened to the pork industry over animal welfare.
"People want to see us get back to more honest values and transparency and integrity around what we are purchasing. It's not just happening in food, it's happening in a whole range of areas.''
Packaging is another issue. Many food items come in several layers of packaging - a box, a tray and plastic wrap, which all have to go somewhere and cost to be got rid of.
''We pay for it in our rates and we have huge landfill costs. I don't buy meat in meat trays and I'm staggered by the number of people who don't take their own bags to the supermarket and come away with umpteen plastic bags.
"Those plastic bags blow everywhere and have an impact on marine environments; they have an impact on our landfill.
"We have technology and people who can supply biodegradable trays and bags to supermarkets. The problem is they cost more,'' Dr Law said.
''You have this tension all the time between the impact on the environment and the cost to the supermarket or the consumer.
"There is cost everywhere but the point is we haven't got another planet to go to and if we keep stuffing up this one the way we are, and not just in terms of food waste but all sorts of waste and all sorts of impact - CO2 emissions and everything else - then we have major problems.''
He gives an example: if nitrates from intensive dairy farming get into Canterbury aquifers that supply water to towns and cities, everyone will need a water filter.
Who would pay for that?
Would it be the dairy industry or individual consumers?
And what about those who couldn't afford a water filter, would they have to drink dirty water?
Sustainability was also about cost.
There have been issues in New Zealand supermarkets on the cost of milk and the cost of fish, he said.
''If a fisherman lands fish at the wharf and he's paid $4 for it, he still has to maintain his boats and gear and staff, yet when the supermarket's putting that fish out at $35 or $32 a kg, then who's making money out of that?
"There's issues over equity and social justice. Everyone will claim their costs means that's what they have to charge, but if that's the case, then it's not sustainable.''
The ''huge'' issue around inequitable access to food on the one hand, and the massive amount of food waste each year on the other, is startling, Dr Law says.
According to FAO statistics about a third of the food produced in the world for human consumption every year - about 1.3 billion tonnes - is lost or wasted.
''One of the biggest issues in the future will be our ability to feed the global population.
"Some countries will feed themselves and some won't, and again that comes back to the issue of social injustice and social equity and being able to provide people with their basic needs, which are shelter, clean water and food.
"While some do that in an excessive way, others have limited access to water or part of their day is just having to walk miles to get fresh water because it isn't available.
"I think along with climate change, water is going to be our biggest single critical issue. We need water to grow food.''
On a recent visit to Canada, Dr Law found most of the environmentalists on Vancouver Island were ex-loggers or ex-fishermen, because they saw the impact of their industries on the environment and the fish had gone.
Another concern is the amount of chemicals in food - some people are no longer prepared to pick up an apple with a mark on it but it may be an organic one that's clean because of the sprays that haven't been put on it.
''You only have to do a swab test on one of the banana boxes to realise there are chemical residues on them because of the spray they use on bananas,'' Dr Law said.
Accreditation by independent third-party auditors, such as organic certifiers, Conscious Consumers, Fair Trade, or Blue Tick, is becoming increasingly important for consumer confidence in the integrity of marketing claims.
Recently Dole scrapped the ''ethical choice'' label it stuck on its bananas without third-party accreditation after an investigation by Oxfam and consumer complaints that it was misleading, Dr Law said.
Issues of sustainability are complex. It would seem that exporting our meat to Europe would be unsustainable but that is not actually the case.
''We can still do that with a lower carbon footprint than they can with their own animals in the UK.
"That is because when you look at the total impact, the total carbon, their animals are in barns, so there's a barn construction required, they are fed grain so you've got grain production that adds to that, and all the transport of that grain and whatever else.
"When you put all that carbon together with our cattle that are grazed in pasture in the high country, we can still get that meat to the UK with a lower carbon footprint.''
Dr Law and his Sustainability Company work with businesses in New Zealand and Australia to develop sustainable business practices, but ordinary consumers could make a difference by making ethical and sustainable choices about what they bought and what they did, he said.
Dr Barry Law will be speaking at the New Zealand Guild of Food Writers' conference on sustainability in Dunedin from Friday to Sunday. Registration is open to the general public: visit www.foodwriters.org.nz