Science - February 2, 2015

New test detects radioactive food fast

Text:
Rob Ramaker

It was a small news bulletin that came out around Christmas: There was no wild boar on the shelves at Albert Heijn this year because the meat was suspected of being radioactive.

The boar, from German forests, had eaten wild mushrooms containing traces of radioactivity going back to the Chernobyl disaster in 1986.

This is unusual news, says Puck Brandhoff, a researcher at Rikilt. Radioactivity in food is very rare in the Netherlands. Nevertheless, it is important to be prepared for radiation accidents. By way of illustration: in 1986, the Soviet Union only admitted that an accident had taken place when the Geiger counters broke down thousands of kilometres away in Sweden.

With the technique now in standard use it takes about three days to take a measurement. In the January edition of the Journal of Environmental Radioactivity Rikilt published three much faster methods of testing whether food is contaminated. These methods take roughly half a day (between 1.5 and 7 hours) to test the food. The new methods are less sensitive and are mainly intended for use straight after a radiation accident, so that in an emergency situation it is soon clear which food is safe and which is not.

 

BETA RAYS

Even when there is no known risk, Rikilt tests samples of Dutch milk, vegetables and other food for radiation. About 45 food processing factories have measuring equipment which checks for gamma rays. This is the least harmful but most far-reaching type of radioactivity. In the lab on the Wageningen campus, researchers also test samples for alpha and beta rays.

These sources of radiation do more damage as soon as someone swallows them. Outside the body they are less dangerous, but are more difficult to detect. Samples in the laboratory are therefore carefully prepared in a time- consuming process in which the food is dried, heated to 550 degrees Celsius and crumbled to ash. Only after that can the level of radiation be measured using a ‘scintillation counter’. It is precisely in these preparatory stages that the new methods save time.


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