The new food scare over dioxin-contaminated pork has a wearying familiarity about it. First, there's the shock announcement that the suspect foods have been cleared from supermarket shelves. Then, the usual experts get paraded before the media with a reassuring message about the risks being very small – a message Michael Meacher is right to question.

Food safety agencies are called in to carry out urgent investigations, implying that such events won't be allowed to happen again. News gatherers ratchet up the drama with grim stories of the effects of whatever the particular poison happens to be. Farmers and food processors step in to calm the hysteria with claims that the fuss is being overdone and a little bit of contaminant isn't going to do you much harm.

During the current dioxin scare I've even seen a Lib Dem press release calling for better labelling, particularly for ready meals. The suggestion is that contamination is all to do with foreign foods, and if we could only be sure our pork pies or microwave-ready toad-in-the-hole were made from good British ingredients, we'd be safe.

It's nonsense, of course. When it comes to safety, what matters is not where a food is produced, but how. And with our present large-scale, centralised, industrial production systems, food scares are inevitable.

I've a farmer friend who regularly raises a few pigs on her mixed farm. Her chosen breed is Berkshires, once famed for the quality of their pork. They spend their lives rootling around in pasture paddocks and feeding on a ration based on home-grown barley.

In due course, they're trucked off to the nearest abattoir for slaughter. The butchered meat is then returned to my friend's farm for sale to friends and locals. It's inconceivable that meat like this could be contaminated by dioxins or any other industrial poison.

If the unimaginable happened and a freak storm should dust the pasture with dioxins or PCBs from heaven knows where, even then the consequences would be limited. The contamination would be localised and contained.

Our industrial food systems, however, make intermittent catastrophes almost inevitable. Pigs are all too often crowded together in sheds and fed rations formulated from any number of globally-traded industrial grains and food by-products.

As I write, speculation has it that the current incident was caused by contamination of animal food with non food-grade oil such as diesel fuel, or with plastic food wrappings. Whatever the cause, once meat has become contaminated the highly-centralised nature of our food system makes wide-scale poisoning far more likely. Contaminated meat can quickly find its way into products that may be sold in a number of countries. Tracing contamination becomes a nightmare; avoiding such foods virtually impossible.

In their bid to reduce the risk, food safety agencies rely on hazard analysis to identify those parts of the process where contamination is most likely. But so extended is the global food chain that nasty surprises are inevitable from time to time. It's also inevitable that those of us who live on industrial foods will get an occasional dose of pollutant.

If you're not happy with the risk-analysis route to healthy eating, the best advice I have found is to make sure your pigs – and cattle and sheep for that matter – are raised on grass. And don't be put off by the fact that you live in town. I know a West Country pig farmer who makes a good living by supplying pigs direct to city folk.

He raises them – on pasture, of course – feeds them on a home-grown ration, has them slaughtered, then delivers the meat to the owner. Having paid up front, the owner gets a photo of his or her animal and is free to visit them on the farm if they wish. It looks to me like a fairly foolproof way of getting worry-free pork, or pretty well any other animal food come to that.

It doesn't even have to be expensive. Buying direct from the farm, consumers can often get this sort of meat at the price they'd pay in supermarkets for the hazard-assessed version. Whatever else its failings, industrial agriculture was supposed at least to deliver cheap food. Unfortunately, it doesn't even do that – especially when the cost of food scares is factored in.