11th January: Milk Day

Today is Milk Day. Ten things you may not know about milk:

1. Cow’s milk was first drunk by humans 10,000 years ago in what is now Afghanistan and Iran.
2. Scientists think the ability of humans to digest cow's milk is the result of a chance mutation somewhere in Europe. Before that, only children could produce lactase, an enzyme necessary for digesting the lactose in milk and the ability was lost in adulthood. This could explain why huge numbers of people are lactose intolerant in the USA, including 75% of Native Americans and African Americans, and 90% of Asian Americans. Lactose intolerance is less common among those descended from northern Europeans. It could be argued, then, that anyone who is not lactose intolerant is a mutant and their super-power is digesting milk!
3. Cow's milk contains, on average, 3.4% protein, 3.6% fat, and 4.6% lactose, 0.7% minerals and supplies 66 kcal of energy per 100 grams.
4. The white colour of milk is caused by light reflecting off the fat in it.
5. Cows are not the only animals whose milk is drunk by humans. Others include buffalo, Goat, sheep, Camel, Donkey, Horse, Reindeer and yak.
6. Mammals are known to produce milk but they don't have an absolute monopoly. Some birds produce a milk-like substance to feed their young as well. Pigeon milk is generated inside the crop, a storage area in the oesophagus, and is a vital part of the diet of baby pigeons.
7. India is the largest producer of milk products followed by the United States of America, China, Pakistan and Brazil. The country which consumes the most milk per person is Ireland, where they consumed 135.6 litres each per year in 2011.
8. Milk was first packaged in glass bottles in the 1870s in New York. The idea caught on in England in 1880. In 1884, Hervey Thatcher, an American inventor from New York, invented a glass milk bottle, called 'Thatcher's Common Sense Milk Jar', which was sealed with a waxed paper disk. Plastic coated paper cartons were introduced in 1932. Milk is rarely sold in glass bottles now.
9. Pasteurization was originally developed as a way to stop Beer and Wine from going off, and it was 20 years before it was used for milk.
10. According to a 2001 study by researchers at the University of Leicester, playing slow songs to cows increases their milk production. Perfect Day by Lou Reed, Bridge over Troubled Water by Simon and Garfunkel, What a Difference a Day Makes by Aretha Franklin, and Everybody Hurts by R.E.M. were found to be particularly effective.