Stocks of cheese are at their lowest since 1971 and cheddar is up 81% since November 2002 due to an increase in popularity of low-carb diets.

As manufacturers and suppliers pass on the added cost of cheese, pizza companies are reported to be suffering in Australia, the US and the UK.

The world price of mozzarella rose to $3,060 a tonne this month from $1,940 two years ago.