TOKYO, June 2 — Before March 11, 2011, procuring food for an average Japanese household was a pretty straight-forward affair.

Following long-established traditions, a housewife — it is, still, almost always a woman in charge — did her best to ensure that every product brought to the table could be traced to Japanese soil or waters.

This, it was widely held, was the best way to avoid eating fish, meat or produce tainted with dangerous contaminants. Chinese imports were to be avoided whenever possible.

A shopper buys cabbages at a supermarket in Tokyo. After the Fukushima nuclear accident, some Japanese consumers didn’t hesitate to shell out thousands of yen to have their supermarket purchases examined for traces of radioactivity on their way out of the store. —AFP pic

The accident at the Fukushima nuclear power plant, unleashed by a devastating earthquake and tsunami, shattered this age-old faith in the purity of Japanese produce.

Even the country’s most cherished and emblematic staple, rice, has been tainted in a way that was unimaginable before March 11.

The very products — many of them cultural icons — that had always been deeply reassuring precisely because of their native origins, were suddenly perceived as potentially poisonous, transformed overnight from sources of comfort to objects of fear.

Nuclear radiation is scary stuff. A quarter century after Chernobyl, and more than 65 years after atomic bombs laid waste to Hiroshima and Nagasaki, fatally sickening thousands not killed outright, even unfounded fears of radioactive contamination can spark panic.

Japan’s catastrophe emptied pharmacies in North America and Europe of anti-radiation pills despite reassurances from all manner of experts that the danger was nil.

By contrast, there are any number of agents — cancer, AIDS and auto accidents, to name three — that claim millions of victims every year but do not inspire that same kind of terror. People still smoke, practise unsafe sex and climb into their cars every day.

So why is nuclear radiation so fearsome, and what determines how we react when faced with a threat, imagined or real?

The answer is complex and laced with contradictions, starting with the fact that most people don’t even think twice about absorbing radiation doses delivered through medical X-rays or scans.

But put the words “nuclear” and “accident” together, and suddenly the idea that sub-atomic particles can slip through our skin to damage inner tissue, or seep into the food we eat and the air we breathe, sets spines shuddering.

“Anything that can penetrate inside our bodies fills us with apprehension, and triggers an ancestral or ancient fear,” said Herve Chneiweiss, a neurologist at the Centre for Psychiatry and Neuroscience at Universite Paris Descartes.

When the culprit is invisible, odourless, tasteless — beyond, in other words, the reach of perception — that angst is magnified even more.

The partial meltdown of three reactors at the Fukushima Daiichi plant released caesium particles and other radioactive elements into the air, soil and sea.

Unlike harmful iodine 131, which disappears in matter of days, caesium 137 has a “half-life” of 30 years and lingers even longer.

Radioactive discharge from the crippled power station fell directly on crops and vegetables, and worked its way into the food chain when fish or animals in affected areas consumed contaminated plants.

Even as the reactors continued to spew nuclear detritus, health officials began to monitor radiation levels of food products around the country and essentially quarantined a large swath of agricultural land and fishing grounds around the plant, located some 250km northeast of Tokyo.

But spot checks in areas well beyond Fukushima — including around the capital — showed that potentially harmful radiation had been carried far afield by the wind and ocean currents.

Official statements on what did or did not constitute dangerous levels of contamination varied, adding to the confusion and concern.

To allay their fears, many Japanese consumers took matters into their own hands. Some didn’t hesitate, for example, to shell out thousands of yen (several dozen euros or dollars) to have their supermarket purchases examined for traces of radioactivity on their way out of the store, a service offered by several municipalities.

Private companies such as Bekumiru — literally meaning “see the becquerels”, in reference to the unit used to measure the amount of radiation emitted by a source — rent out self-service detectors.

In Kashiwa, a city near Tokyo that at various times has shown abnormally high levels of radiation, the company’s offices are never empty and the phones never stop ringing.

“The people who live here are especially worried,” notes the site manager, Motohiro Takamatsu.

“Clients come with their vegetables, a bowl of rice, water or any other food stuff,” he explains. “They do the measuring themselves — it’s more reassuring that way.”

A user guide next to the machines, which take about 20 minutes to complete an analysis, lists the legal safety limits for each food type in becquerels per kilogram (Bq/kg).

“I grow veggies in the courtyard of the kindergarten where I work, and since the children eat them I come here regularly to reassure the parents,” said Ryotaka Iwasaki.

“I don’t know what I’d do if this service didn’t exist, because it would cost too much to have specialists come to the school.”

For Mitsue Suzuki, in her sixties, Bekumiru is a way to be sure that she isn’t poisoning her customers. “I came to test the rice I grow. It has already been approved for sale, but I wanted to verify myself.”

One large supermarket group, Aeon, has set up its own testing regimen to regain the confidence of consumers.

Setting a “safety threshold” for radioactive contamination, as has done the government, is not good enough, argues the chain’s deputy general director, Yashide Chikazawa: “Only products that have undetectable levels of radiation can compete with imported products now.”

Aeon’s “zero tolerance” policy was at first met with howls of protest by suppliers in affected areas, but they came around to the idea that it was the only way to reassure a nervous public, he said.

They have reason to be sceptical. After the accident, the government raised the tolerable limit of contamination to 500Bq of caesium per kilo, following international emergency guidelines.

But consumers did not fail to see that products that previously would have been tossed in the rubbish as potentially toxic were now on the grocery shelf.

As of April 1, the threshold has returned to pre-accident levels: 100Bq/kg for most products, 10Bq/kg for a litre of water, and 50Bq/kg for food consumed by infants.

But the temporary relaxing of standards nourished the widely-held idea that the government was more concerned about producers than the public.

The recent and unexpected detection of elevated radioactivity — up to several dozen millisieverts (mSv) per hour compared to 0.2mSv before the nuclear meltdown — in cities relatively distant from Fukushima feeds into these suspicions.

“The wind and rain transported radioactive elements,” explained scientist Tatsuhiko Kodama, an expert on the impacts of radioactivity.

The government had defined the large zones of contamination, but has not been able to keep track of smaller, shifting “hot spots,” so many people have taken to wearing inexpensive Geiger counters that bleat a warning when radioactivity climbs.

Beyond rational concerns, say scientists, radiation also inspires more primal anxieties. For evolutionary psychologists, who argue that human behaviour is deeply rooted in natural selection and the need to adapt to our environment, fear of radiation also taps into the apprehension of our distant forbear about contagious disease.

Even if early man could not see viruses or bacteria, he was confronted with their lethal impact. “People treat nuclear contamination as if it were disease contamination — emotionally, they think about mere exposure and not dose,” said John Tooby, a professor at the University of California at Santa Barbara and an expert on the evolutionary origins of emotion.

“Although we live bathed in a sea of background radiation, people treat any increment as a dire risk.”

In the case of Japan especially, such gut-level reactions are overlaid with historical knowledge of both the atom’s terrible power and the unpredictable conditions under which it can be unleashed. — AFP-Relaxnews