Fuel surcharges are being added by food distributors in the U.S. because of the rise in costs of shipping certain types of food such as highly perishable fruits and seafood imported from far away, reports The New York Times.

As the war in Iran pushes up the price of a barrel of Brent crude, the international benchmark, up 56% since the war with Iran began, the average price of diesel, which is used in trucks and planes that move food and other cargo, is up 44%. The Times says that, if the war continues, the cost pressure on businesses up and down the supply chain is likely to worsen.

Grocery stores, restaurants, hospitals and even schools are most likely seeing costs for their food shipping climb. Many of the nation’s largest food distribution companies, including Sysco, U.S. Foods and Performance Food Group, impose fuel surcharges in line with national diesel prices.

The Independent Grocers Alliance, a group of 2,600 independent grocery stores, said on its website last week that price increases on shelves might not be apparent until midsummer, noting that it will take time for various fees to work their way through the supply chain.