Do you have any idea where your food came from?

Where does your food come from? A few years ago, most consumers were satisfied with a sticker showing the country of origin.

But concerns about fair trade and the environment, as well as food safety, are now driving a wave of projects aimed at tracking food from farm to shopping basket.

Though price is still the main factor determining the food that people buy, many are demanding to know more about its source. This is partly due to a series of recent food safety scandals, from major outbreaks of salmonella and E. coli to melamine showing up in baby formula and pet food.

"The public want to know where their food and other products come from, how they are made, and whether they contain any 'unhealthful' contaminants," says Dara O'Rourke, an environmental policy expert at the University of California-Berkeley. Ethical and environmental concerns figure prominently, too. In the United States, for example, "a small but rapidly growing percentage of the population - perhaps 8 to 10 percent - are deeply interested in these issues," says food policy expert Marion Nestle of New York University. "Interest in where food comes from is part of a growing social movement."

Most manufacturers already use bar codes or RFID chips to track their products. But with the help of cheap cell phone and Internet access it's becoming possible to collate data from remote locations around the world and make it available to the people who are going to eat the food.

In many cases, manufacturers recognize that disclosing the source of their food is good for business. Sime Darby, a large palm oil supplier in Indonesia and Malaysia, is working with FoodReg, a firm based in Barcelona, Spain, that develops food-tracking software. The idea is to develop a system to prove to customers that its crops are not grown on land recently occupied by tropical rain forest.

In remote regions where farmers don't have access to computers, they can use cell phones to record onto FoodReg's online database the time and place the crop was harvested. Tracking systems like this should also make it easy to calculate the distance that goods travel to reach stores, allowing consumers to estimate the greenhouse gas emissions racked up by the transport of their food.

"The calculation of food miles and carbon footprint could be the killer application for traceability," says Heiner Lehr of FoodReg. TraceTracker, a Norwegian company formed in 2000 in response to a series of food safety scandals in Europe, also makes online databases that allow food to be tracked. It is collaborating with telecommunications company Intel to track halal food.

They hope to develop a cheap mobile phone that farmers, suppliers and processing houses could use to load information about the production of food onto TraceTracker's database. Consumers could then use their own smart phones to check that the food they are buying comes from a licensed halal source.

"It's much harder to cheat if you have electronic traceability," says Knut Jorstad, TraceTracker's chairman.

Other efforts aim to provide independent information about food in stores. Simon Kelly of the Institute of Food Research in Norwich, UK, and colleagues are using isotope analysis of chicken meat to check where and how the birds were farmed. The ratio of carbon isotopes in the meat shows how much corn the birds were fed relative to other grains, while hydrogen isotopes reveal the amount of rainfall where they were raised.

In theory, they say, it should be possible to pin poultry down to a particular region or county - useful for customers who want to avoid poultry from areas affected by bird flu, or who only want to buy locally sourced food.

Meanwhile, an online initiative called the Fair Tracing Project aims to publicize how farmers in poor countries are treated by the multinational companies that sell their produce. Farmers use mobiles to upload photos and videos "so they can tell a story about the labor conditions they're working under," says Fair Tracing team member Dorothea Kleine of Royal Holloway, University of London. There are already several phone applications that customers can use to check the origins of certain foods, such as Good Guide, which ranks products according to environmental, health and social measures, and Locavore, which uses an iPhone's GPS system to detect where the user is, then displays a list of local foods that are in season, with locations of nearby farmers' markets.

But that's just the beginning, according to Jorstad. If the various initiatives start collecting their data in a standard format, all the different databases could be linked together in one huge "Internet for food."