ROME (AP) — More than 70 countries have pledged to do more to cut down on the amount of food lost due to poor refrigeration.

The countries signed the pledge Saturday at an annual meeting of the Montreal Protocol where ministers, government officials and experts work on regulating man-made chemicals used in refrigeration and air-conditioning systems that are harmful to the ozone layer. The meeting took place at the United Nations' Food and Agriculture Organization headquarters in Rome.

About one-third of the world's food is lost or wasted and the hope is that developing better methods to keep food cold while it's stored and transported will reduce waste.

Poor refrigeration leads to the loss of about 9% of perishable food in developed countries and about 23% in developing countries, where millions of people suffer from malnutrition.

Experts say better refrigeration would help reduce greenhouse gas emissions and the harmful gases used in refrigeration and air-conditioning systems.

The United States, China, European Union members and many nations in the Americas, Africa and Asia signed the pledge.