Food, Inc (PG)

A shocking, if preachy, exposé of the food industry.

Where there is an exposé of the American food industry, Eric Schlosser will not be far away. Even before his name appeared in the opening credits of the documentary Food, Inc, I thought I recognised the reassuring voice, as soothing as the anaesthetist counting you down from ten, which was pondering the ability of supermarkets to transcend the seasons. Now it's asparagus in November, strawberries for Christmas. All must have parsnips! And consider, if you will, the ubiquitous tomato.

“Although it looks like a tomato, it's kind of a notional tomato," purrs Schlosser. "The idea of a tomato." It's a good starting point, that pseudo-pomodoro, for a film that wonders how our delusions - about where food comes from and what it will do to our bodies - have come to overrule reality.

Schlosser wrote Fast Food Nation, and co-scripted Richard Linklater's fictionalised adaptation of the book. Although not written by him, Food, Inc feels like an attempt to claim back the subject from Linklater's unloved film. Some of the material here will be familiar from the earlier book and movie, in a greatest-hits sort of way: the exploitation and betrayal of migrant labour, the ease with which ammonia and faecal matter find their way on to the dinner plate. (As a cattle trader in Fast Food Nation, played by Bruce Willis, reasoned: "We all gotta eat a little shit from time to time.")

Food, Inc isn't preoccupied with lobbing rotten tomatoes, notional or otherwise, at the fast- food business, though it does demonstrate how the industry's philosophy - that instant gratification is simply too slow in coming - has permeated food production beyond the golden arches. But the picture also shows how consumption, farming and obesity levels have been dictated by a dependency on corn. It is the great stowaway in our larders; if there's an ingredient that is a bit of a mouthful (maltodextrin, ethyl lactate), chances are it's derived from that crop. The animals we eat are reared on the stuff (or other grain). Research shows that a corn diet leads to a higher incidence of E coli in cattle, but at least it gets cows nice and plump in no time. Truly we have become children of the corn.

“Then why eat factory-farmed meat?" I hear you cry between mouthfuls of salad. (Don't get too smug: there are many cases of spinach carrying E coli.) The film sets out the economic reasons as it goes shopping with a Mexican family whose budget is already eaten into by the cost of the father's diabetes medication. A head of broccoli sets them back $1.29, whereas a cheeseburger, grabbed at a drive-thru at the start of the working day, is $1 a pop.

Not that it would make any difference if they could afford steak Diane: 80 per cent of the US meat industry is controlled by the top four beef suppliers, who all preside over Concentrated Animal Feeding Operations (Cafos). The film contains footage of these Cafos, where each animal, you'll be surprised to learn, does not get its own en suite bathroom. But then the industry is big on banal euphemism.

Take the "redesigning" of the modern chicken, which might conjure images of a fancy makeover prior to a credit-card blowout on Rodeo Drive, but in fact refers to changes in the animal's breast area, which has been artificially enlarged to meet the demand for white meat. Step forward, the modern chicken, from birth to 5½lbs in seven weeks. I say step forward, but with that amount of heft on its puny bones, chance would be a fine thing.

Food, Inc moves towards a positive conclusion, taking heart in consumers' ability to vote for organic produce at the checkout, and comparing the fight for better food production with the successful campaign against the tobacco industry. But one problem for those of us whose viewing habits were transformed by The Day Today is that we lose both faith and composure at the first sign of wacky graphics; how unfortunate, then, that the film-makers are fond of plastering statistics on to the sides of animated cattle heading to the abattoir on conveyor belts. A series of pious closing messages also sticks in the craw. Bumper-sticker slogans such as "Cook a meal with your family and eat together" and "If you say grace, ask for food that will keep us healthy" had me briefly craving a patty in protest.