Scientists test toxicity of extra toppings

Researchers from China and Australia have found fluorescent nanoparticles on cooked pizzas. 

Manufacturers sometimes add nanoparticles to food to keep it fresher for longer, to thicken or change its colour, or to add nutrients. However, some cooking processes, such as baking and barbequing, can also generate carbon nanoparticles on food. 

Previous studies have found such nanoparticles on chicken, hamburgers, seafood and even in liquids such as coffee and beer. Now, Shuang Cong of Dalian Polytechnic University, and colleagues, have added pizza to that list. They analysed pizza with x-ray spectroscopy and Fourier-transform infrared spectroscopy and discovered fluorescent carbon nanoparticles form out of ingredients that contain proteins, polysaccharides and lipids. 

They also investigated the properties, biodistribution and cytotoxicity of the pizza nanoparticles. These tests showed that the nanoparticles could move into the tissue and organs of worms that were fed the fluorescent nanoparticles. And tests using normal rat kidney (NRK) cells indicate that the nanoparticles can interfere with the cell cycle. 

The researchers suggest that people should avoid eating charred food that is heated to high temperatures for long periods.