It doesn’t do to be complacent about the safety of our food supply. Just when you think everything is under control and the systems developed to manage hazards in the supply chain are working well, along comes news that puts a large spanner in the works. It could be something new and previously unsuspected, like acrylamide in 2002, or a familiar problem where established controls have failed. The last few weeks have seen examples of both.
A study by scientists at the University of Derby – published a little while ago, but now attracting attention – identified high levels of fluoride in some types of tea on sale in the UK. Too much fluoride in the diet is not good for your teeth or bones, and over time can lead to potentially serious health effects. The researchers unexpectedly found that levels in some supermarket own-label economy tea blends were high enough to exceed the dietary reference intake level for fluoride in adults drinking more than a litre every day. That’s about four cups – hardly excessive! The problem seems to be that cheap tea blends are likely to use more mature leaves. The tea plant accumulates fluoride from the soil as it grows so that older leaves contain more. Some of the blends featured in the study may have to be reformulated.
Shellfish toxins are better known hazards than fluoride, but that doesn’t mean that controls are always effective, as I’m sure the 70 people in southeast England who recently suffered the symptoms of diarrhetic shellfish poisoning would agree. The culprit seems to have been mussels from Shetland. Fisheries around the UK are regularly monitored for rising levels of toxic algae and for associated toxins, and are closed when high levels are found. This is currently the only practical control, but it clearly failed on this occasion. Fortunately diarrhetic shellfish poisoning is not too serious, but there are other types that can cause severe neurological symptoms. It looks as though monitoring for toxic algae may need to be improved, especially now that water temperatures in the seas around Britain are rising.
The lesson from both of these stories is simple: food safety professionals cannot afford to relax for a second.