Doctors commonly give patients with coeliac disease and their families three pieces of kitchen advice when diagnosed: buy a second toaster, use separate knives for gluten-containing foods and cook pasta in two pots. 

But a small US study suggests two out of three of these tips may not be necessary after researchers tested how much gluten transfer occurred in the three kitchen scenarios. 

The threshold level for gluten is considered to be 20 parts per million (ppm) in the US, Europe and the UK, where foods with this level or below can be labelled gluten free (GF). 

In their study in Gastroenterology, the researchers found: