altitude froze it. B-17 crews in Europe did something similar on their bombing runs as did others. Retail sales Ice cream can be mass-produced and thus is widely available in developed parts of the world. Ice cream can be purchased in large cartons (vats and squrounds) from supermarkets and grocery stores, in smaller quantities from ice cream shops, convenience stores, and milk bars, and in individual servings from small carts or vans at public events. In 2015, the US produced nearly 900 million gallons of ice cream. Specialty job Today, jobs specialize in the selling of ice cream. The title of a person who works in this speciality is often called an 'ice cream man', however women also specialize in the selling of ice cream. People in this line of work often sell ice cream on beaches. On beaches, ice cream is either sold by a person who carries a box full of ice cream and is called over by people who want to purchase ice cream, or by a person who drives up to the top of the beach and rings a bell. In the second method, people go up to the top of the beach and purchase ice cream straight from the ice cream seller, who is often in an ice cream van. In Turkey and Australia, ice cream is sometimes sold to beach-goers from small powerboats equipped with chest freezers. Some ice cream distributors sell ice cream products from travelling refrigerated vans or carts (commonly referred to in the US as "ice cream trucks"), sometimes equipped with speakers playing children's music or folk melodies (such as "Turkey in the Straw"). The driver of an ice cream van drives throughout neighbourhoods and stops every so often, usually every block. The seller on the ice cream van sells the ice cream through a large window; this window is also where the customer asks for ice cream and pays. Ice cream vans in the United Kingdom make a music box noise rather than actual music. Ingredients and standard quality definitions Many countries have regulations controlling what can be described as ice cream. In the U.S., the FDA rules state that to be described as "ice cream", a product must have the following composition: greater than 10% milk fat 6 to 10% milk and non-fat milk solids: this component, also known as the milk solids-not-fat or serum solids, contains the proteins