GIVE US OUR DAILY BREAD

SEALED IN plastic and chilling in a Key West grocer's cabinet, the cheese sandwich looked fresh enough. But outside in the Florida sunshine, the sell-by date alerted me to the fact that there was more in this sandwich than a bit of cheese. The abundance of additives and preservatives had given this simple snack the staying power of six weeks' shelf-life. Inspired by this sandwich (which tasted awful), I decided to investigate the science behind modern food production for a BBC World Service series, Science on a Plate, and see what was in store for the future.

Nineties Britain has shaken off its culinary stereotype of fish and chips. There is a boom in fashionable cook-books, exotic ingredients, gourmet home-cooking. Today, according to the TV versions of best-selling recipe books, we are apparently rustling up bruschetta one week and hosting a three-course dinner for 30 the next. Never before has the nation's appetite for cooking and new ingredients been healthier, it would seem.

Joanna Blytheman, the author of The Food We Eat, keeps a critical watch over manufacturers and believes that the scare over BSE was a wake-up call to the consumer to question the quality of our food. "We're seeing the downside of the technological wizardry that's supposed to make our food perfect and bring us all these so-called benefits. We've seen it already with things like pesticides and we're beginning to see the problems that will happen if we go ahead with genetically engineered foods. I think the consumer reaction is 'stop, we're not impressed by technology, we want to go back to basics'."

But for all the quirky programming and culinary glitz on the small screen, is there any evidence that the ordinary loyalty card holder in the supermarket aisle is applying pressure on the manufacturers? Flicking through the food industry's trade press you would be hard pressed to find any signs of it, judging by the innumerable advertisements for highly processed and synthetic ingredients.

Forget organic, natural, tasty and free-range. High volume, low cost, high-tech and uniform appearance are the buzz words of today's food producers. A good example of this, I discovered, is the state of bread-making in Britain. For centuries, baking was a small-scale, localised industry. In 1961, the Chorleywood Bread Process revolutionised all that. This is totally automated bread-making, and it reduced the time it takes to ferment dough from around three hours to three minutes via a "high-speed intense mechanical working of the dough". Not only faster, this process allows the manufacturer to use poorer and cheaper varieties of wheat.

One food technologist I interviewed for the World Service series was researching the size of bubbles in bread. Was this to improve flavour or quality? No, it would make the loaf "look larger and better value for money," was his response. Gail Stevens is the proprietor of Baker and Spice, a Knightsbridge bakery which specialises in traditional sourdoughs that take 48 hours to produce. "Most of the population have forgotten what real bread tastes like. People have no idea what a good, fresh bread product is. Mothers don't buy it, children don't eat it. In most places in Britain you have no choice but to buy 'plastic' bread."

However our bread is made, the margarine that we spread on it has not escaped the scientist either. The fad for low-fat foods (and the money to be made there) has challenged the technologist. At its most simple, margarine is just chemically-hardened vegetable oil. High in less saturated fats, it is marketed as a healthier alternative to butter. Producing a low-fat margarine means replacing some of the vegetable oils with water. But as we all know from textbook science, these do not mix and so emulsifiers and other additives are necessary to improve the consistency and colour of the spread.

Now technologists have taken the alleged health benefits of margarine one step further with the development of a spread containing sitostanol ester, said to inhibit the absorption of cholesterol during digestion. So important is this development that one stock-market analyst has called this product "much more significant than NutraSweet." And its price seems to bear out his prediction - it is already on sale in Finland at four times the cost of butter.

Oils are at the forefront of another so-called "health revolution". Olibra is described as the first ever all-natural food ingredient to suppress appetite; it's an emulsion "based on fractions purified from palm and oat oil". Launched by Safeway across the country this month, Olibra has been incorporated into a range of yoghurts called Maval, which stimulates the body's appetite control system in the small intestine to producing a feeling of "fullness" which can last up to six hours. There has been a scramble of manufacturers, who are now in discussion with the makers of Olibra to incorporate it into other products aimed at the huge market for diet foods.

But if consumers feel powerless, faced with increasingly synthetic ingredients and processing technologies, they can take some comfort from the short history of food irradiation in Britain. It was customer concern about the safety of irradiation that pressured all the major supermarkets chains into saying that they saw no use for it. By exposing foods to small doses of ionising radiation, bugs and bacteria are destroyed, reducing the likelihood of food poisoning and spoilage. According to the Institute of Food Technologists in the United States, foods processed correctly are safe and wholesome and food does not become radioactive. In the US, irradiation is approved for use on fruit and vegetables, spices, pork, poultry and red meat.

The next big consumer battle has already started, with mounting public debate over the introduction of genetically modified foods. By transferring the genes which control certain characteristics from one species to another, scientists have produced crops which are resistant to pesticides and to insects. Two supermarket chains are currently selling a tomato paste produced with a modified tomato bred for its improved taste and texture. Another idea under development in the lab is a strain of rice genetically altered to be rich in vitamin A - a useful food for areas of the world where nutrition is poor.

Prince Charles's high-profile comments in the press earlier this month against genetic modification are viewed by scientists as a setback to public understanding of the issue. Jim Dunwell, Professor of Plant Biotechnology at Reading University, believes the public is getting carried away by poor reporting and sensational headlines.

"What the public doesn't realise is the extent to which we have already been altering existing plant varieties by selective plant breeding. This form of genetic modification has been going on for almost a hundred years. All we're doing is taking the technology up a level by adding one or two genes to a plant to improve its performance. It's not such a radical technology as some people suggest."

But Joanna Blytheman is critical of these claims. "The proponents of genetic modification love to say that this will feed the world and solve all our food problems. We need to be extremely cynical - these are the same people who gave us the Green Revolution who promised that pesticides would make food shortages a thing of the past."

Technology is supposedly here to make our lives easier and to produce goods that are more affordable: this is the case with baked beans as well as cars. Understanding exactly what goes into our food, as well as how it is produced, is a challenge. It may be a cliche, but if we are what we eat, don't we have a right to know?

! 'Science on a Plate' is on BBC World Service on Saturdays on 648 MW at 9.15am (SE only), on short wave in the 25 & 31 metre bands and on the Internet at www.bbc.co.uk/worldservice. It will be repeated Sundays, from today on 198 kHz long wave at 2.30am