The science of milk – Jonathan J. O’Sullivan


Why do humans drink so much milk? And given that all mammals lactate, why do we favor certain types of milk
over others? Milk is the first thing we drink, and thanks to developments in the
production and variety of dairy products, it can take on countless forms for our
dietary and sensory well-being. Milk’s primary function is as a complete
source of nutrition for newborns. In fact, since it has all of the vital
nutrients for development and growth, proteins, carbohydrates, fats, vitamins and minerals, and water, milk is the only thing a baby
even needs to ingest for the first six months of life. The unique makeup of milk can vary
depending on factors like species, diet, and location. Reindeer of the Arctic Circle,
for example, make energy-dense milk
that’s about 20% fat, roughly five times more than human
or cow’s milk, to help their young survive the harsh,
freezing climate. So how is milk made? In the uniquely mammalian process
of lactation, a special class of milk-secreting cells
known as mammocytes line up in a single layer around
pear-shaped alveoli. Those cells absorb all of the building
blocks of milk, then synthesize tiny droplets of fat on structures called
smooth endoplasmic reticula. The droplets combine with each other
and other molecules and are then expelled and stored
in spaces between cells. Mammary glands eventually secrete the milk
through the breasts, udders, or, in the rare case of the platypus,
through ducts in the abdomen. Although this process is typically
reserved for females, in some species, like dayak fruit bats, goats, and even cats, males can also lactate. Milk drinkers worldwide consume
dairy from buffalo, goats, sheeps, camels, yaks, horses, and cows. Almost all of these species are ruminants, a type of mammal with
four-chambered stomachs that yield large quantities of milk. Of these, cows were the most
easily domesticated and produce a milk that is both
easily separated into cream and liquid and has a similar fat content
to human milk. In their natural environment, mammals secrete milk on call
for immediate consumption by their young. But with the demands of thirsty consumers, the dairy industry has enlisted methods
to step up production, enhance shelf life, and provide a variety of milk products. In the dairy, centrifugation machines
spin milk at high speeds, forcing less dense fats to separate
from the liquid and float up. After being skimmed off, this fat, known as butterfat,
can be used in dairy products like butter, cream, and cheese. Or it can be later added back to
the liquid in varying proportions to yield different fat content milks. Full fat milk, sometimes referred to
as whole milk, has 3.25% butterfat added compared to 1-2% for low
and reduced fat milk, and less than half a percent
for skim milk. To stop reseparation of the fat
from the water, or creaming, the mixture undergoes the high-energy
pressurized process of homogenization. Before milk hits the shelves, it’s also
typically heat treated to reduce its level of microbes, a government-sanctioned process that raw milk enthusiasts argue
may reduce milk’s nutritional worth. Milk spoilage is started by microbes, which consume and break down
the nutrients in milk. That process causes butterfat
to clump together, leading to a visually unpleasant product. And the byproducts of
the microbes’ consumption are compounds that taste
and smell nasty. But there’s a bigger problem. Raw milk can carry microbes that are
the sources of deadly diseases, so in order to kill as many of those
microbes as possible, and keep milk fresh longer, we use a technique called pasteurization. One version of this process involves
exposing milk to about 30 seconds of high heat. Another version,
called ultra-high temperature processing, or ultra pasteurization, blasts the milk with considerably higher
temperatures over just a few seconds. UHT milk boasts a much longer shelf life, up to twelve months unrefrigerated, compared to pasteurized milk’s
two weeks in the fridge. That’s because the higher temperatures
of UHT processing inactivate far more microbes. Yet the higher processing temperatures may adversely affect the nutritional
and sensory properties of the milk. Ultimately, that choice lies
in the consumer’s taste and need for convenience. Fortunately, there are many
choices available in an industry that produces in excess
of 840 million tons of products each year.

100 Comments

  1. Umaibo said:

    Now do a video on how cows are milked! In the industry…

    August 1, 2018
    Reply
  2. Ahmad Nasser said:

    If this video gets a view added, and it becomes "661,*666*", then I'LL BE DEAD.

    August 1, 2018
    Reply
  3. Emmy Blonde said:

    Milk that can sit out on the counter for a year?? WHAT

    August 2, 2018
    Reply
  4. Ella Smith said:

    what about the animal cruelty of the milk industry 🙁

    August 5, 2018
    Reply
  5. ceefe said:

    In other words, theres no good reason for adults to drink milk from other animals.

    August 6, 2018
    Reply
  6. issa princess said:

    i dont like milk.

    August 16, 2018
    Reply
  7. Charlemagne Evangelista said:

    Why some people are lactose intolerant

    August 19, 2018
    Reply
  8. Ray Day said:

    GIBE ME MILKIES PLAES

    August 21, 2018
    Reply
  9. Davineo said:

    I tought this was gonna be a vegan safe video.

    I was disappointed.

    August 21, 2018
    Reply
  10. Kian Siong said:

    They didn't touch on the bad side of most diary farms 🙁

    August 22, 2018
    Reply
  11. Alveera Rahman said:

    Respect your mother 🙂

    August 23, 2018
    Reply
  12. A. J. R. Wilde said:

    why show a bottle of formula when talking about breastfeeding, idiots

    August 25, 2018
    Reply
  13. febriandri suharto said:

    I love uht milk and greenfield milk☺

    August 28, 2018
    Reply
  14. iActivateMC said:

    I just got a 57-minute non-skippable ad…a like for surviving?! 😂😂😂

    It was supposed to go the other way 😅

    September 2, 2018
    Reply
  15. Suga Kookiez said:

    Alveoli? More like ravioli!

    September 3, 2018
    Reply
  16. Ionut said:

    Milk causes the body to lose calcium since it's very concentrated the body can't process it very good, detects a lot of calcium being eaten, but cannot process it.
    Water may help, but no so much, green vegetables and other products like tomatoes, almonds are rich in calcium.

    September 23, 2018
    Reply
  17. Bakugou Katsuki said:

    I just realozed that those sucker bottles were designed to be like nipples

    September 30, 2018
    Reply
  18. Annie Boom Fannie said:

    Cows milk is
    DEE-SCUSS-SSSSTIIIING!

    October 5, 2018
    Reply
  19. Arun Sooknarine said:

    Omg he said "sheeps"😱

    October 13, 2018
    Reply
  20. El Hombre de oro said:

    I love buffalo milk

    October 17, 2018
    Reply
  21. Hero Number Two said:

    You need sum milk

    October 31, 2018
    Reply
  22. erio milk said:

    0:50 THEY'RE SO CUTE

    breathes

    THE ENTIRE ANIMATION IS SO CUTE

    November 10, 2018
    Reply
  23. Rafael Marzall said:

    Horses are not ruminants. They are strictly herbivore non ruminant.

    November 15, 2018
    Reply
  24. Professor Slime said:

    I hate milk

    November 21, 2018
    Reply
  25. Taczpat said:

    Jonathan J.

    Is this a jojo refrence?

    November 21, 2018
    Reply
  26. Ale GilMen said:

    I thought this was going to go into more science, specifically around breastmilk and breastfeeding.

    November 22, 2018
    Reply
  27. Noah Aubrey Linus Sorensen said:

    sheeps!?

    December 1, 2018
    Reply
  28. SpectreSeven1138 said:

    Sheeps

    December 1, 2018
    Reply
  29. Lisa M said:

    Why do humans drink so much milk?
    Drinks a sip of milk once a month

    December 8, 2018
    Reply
  30. LD said:

    watches as is eating cereal

    December 22, 2018
    Reply
  31. Test1 test2 said:

    Platypuses are so frickin’ weird!

    December 22, 2018
    Reply
  32. black wolf spirit said:

    …but horses aren't ruminants

    December 25, 2018
    Reply
  33. Kaj'Or Reinholdt said:

    Human males can also lactate. It's rare, but it happens.

    December 31, 2018
    Reply
  34. AxolotlMilk said:

    Calcium should be called milk on the element table

    January 2, 2019
    Reply
  35. Moët 111 said:

    I need some milk!

    January 5, 2019
    Reply
  36. Alice Deathbelle said:

    I've always hated milk but I love cheese and yoghurt, I don't get it

    January 6, 2019
    Reply
  37. SuperPowerGames said:

    plant milk isn't milk just swallow this

    January 7, 2019
    Reply
  38. eliza bongiovi said:

    triggered vegans, homosexuals, feminists have left the chat

    January 10, 2019
    Reply
  39. talia maloof said:

    Baby bunnies nurse on their backs.

    January 12, 2019
    Reply
  40. Tran Khai said:

    It's so satisfying when you say "milk":))))

    January 13, 2019
    Reply
  41. via lactea said:

    dont judge people who drink milk not everyone could grow up in 1st world countries with a big variety of food.

    January 14, 2019
    Reply
  42. Bung Scrung said:

    Mmmmmmmm……

    Tiddy joos.

    January 23, 2019
    Reply
  43. Felipe Emos said:

    What about the amount of cruelty in this product? This is a blood product

    January 24, 2019
    Reply
  44. Катя Барковская said:

    Nowadays milk isn't the healthiest product, also meat and vegetables – they are all chemically/ hormonally treated. In substance these product are all healthy, but due to big rates of consumption such treatments are inevitable. Diet is a combination of all products in special proportions, if you are concerned about your diet you can go to a nutritionist and he'll make a right menu for you, and you can take a truthful advice from him, an educated in this sphere of knowledge person, not from the comment section on YouTube

    January 27, 2019
    Reply
  45. Tiny Dinosaur said:

    I only dribk Milk and Water and very rarley I will drink juice or soda. Thats how I am healthy.

    February 2, 2019
    Reply
  46. Lillian Swaim said:

    Gods, how I love dairy, but why is eggs included in "dairy"?

    February 5, 2019
    Reply
  47. Cassy Studios said:

    Why m I watching this when I'm Lactose Intolerant??😑😐

    Still worth it

    February 7, 2019
    Reply
  48. Muhammad Elkhedr said:

    HE NEEDS SOME MILK

    February 15, 2019
    Reply
  49. KARVAK city said:

    Gotla

    February 20, 2019
    Reply
  50. KARVAK city said:

    Vskiw

    February 20, 2019
    Reply
  51. swapertxking said:

    Shame that a large majority of people will never experience the delicious taste and texture of a fine cheese or milk liquor.

    March 5, 2019
    Reply
  52. Jung Chang said:

    The science of milf

    March 13, 2019
    Reply
  53. Vanilla Flexagon said:

    Anyone 2019?

    March 15, 2019
    Reply
  54. Vanilla Flexagon said:

    Btw the animation is so adorable!

    March 15, 2019
    Reply
  55. The Almighty Loaf said:

    So almonds are mammals?

    March 22, 2019
    Reply
  56. I’m watching u UwU said:

    Bewbz

    March 22, 2019
    Reply
  57. mMm Borgers said:

    I wonder what a Cow feels when getting milked 🤔

    March 23, 2019
    Reply
  58. Odett Martinez said:

    I want milk now

    March 24, 2019
    Reply
  59. Mint Diz said:

    thirsty consumers

    March 24, 2019
    Reply
  60. חגי נוימן said:

    Yap, milk. Enjoy https://en.wikipedia.org/wiki/Lactose_intolerance

    March 25, 2019
    Reply
  61. Virdian Sefrizal said:

    🥛🥛🥛

    March 26, 2019
    Reply
  62. dingaring said:

    Did anyone else see milkr

    March 30, 2019
    Reply
  63. Ellie McMurray said:

    Males can lactate? Learn something new every day…….

    April 8, 2019
    Reply
  64. Kevin Besa said:

    Watching this while drinking milk. Awesome

    April 13, 2019
    Reply
  65. Alive Zero said:

    😁😁😂😂

    April 16, 2019
    Reply
  66. Daniel Bendl said:

    I'm just curious…
    Why are we so persistant with trying to drink other mammals' milk, even though so many people even nowadays aren't able to digest it properly?

    May 23, 2019
    Reply
  67. Abbieq11 said:

    Why is that kid in the beginning drinking straight from the carton?

    May 26, 2019
    Reply
  68. Lindamorena said:

    Sheeps is not a word its sheep. Dont @me

    May 26, 2019
    Reply
  69. Alexander Andersen said:

    I NEVER Really liked milk But…..

    I still dont

    June 7, 2019
    Reply
  70. igobivo said:

    Rare ted video i disliked 🙁

    June 12, 2019
    Reply
  71. Indiematic said:

    T I T T Y J U I C E

    June 13, 2019
    Reply
  72. DramaticDraggo said:

    Milk is just filtered blood.

    June 14, 2019
    Reply
  73. Mandar Rane said:

    Can I use the parts of these videos to demonstrate & training purpose?

    June 16, 2019
    Reply
  74. Rabiah Pascall said:

    SHEEP

    June 30, 2019
    Reply
  75. Leema said:

    Lactose intolerants left the chat

    June 30, 2019
    Reply
  76. Mendez Incorporation said:

    Unless your lactose intolerant

    July 2, 2019
    Reply
  77. Peroroncino said:

    I thought Jonathan was an archaeologist

    July 4, 2019
    Reply
  78. Tricus pidbard said:

    Where are my Oreos 🅱️

    July 6, 2019
    Reply
  79. Neelima Goturi said:

    I’m lactose intolerant why am I here??

    July 8, 2019
    Reply
  80. Andrew&Olga said:

    So Gaylord Focker from Meet the parents wasn’t lying.

    July 17, 2019
    Reply
  81. Delta Squad said:

    The science of YEET

    July 24, 2019
    Reply
  82. Dont touch my food said:

    You need some milk

    July 24, 2019
    Reply
  83. mafarmerga said:

    Milk is actually a type of sweat, originally produced not to feed young but as a way of distributing anti-microbial peptides over the surface of the animal.

    July 31, 2019
    Reply
  84. Sprout Does Stuff said:

    I saw the thumbnail I was like educational tiddy 👀

    August 4, 2019
    Reply
  85. Corn Storm said:

    The title is a seed for a jungle in minecraft.

    The science of milk -Jonathan J.

    I cut out a space so the . would fit.

    August 9, 2019
    Reply
  86. Russell from Up said:

    Wait so first 6 months of life a baby doesn’t need food but just need milk? Interesting taking notes

    August 10, 2019
    Reply
  87. Rosalind Kincannon said:

    Do brown cows give chocolate milk ?

    August 11, 2019
    Reply
  88. Mikal Madsen said:

    I wanted to know more about the effects of human milk vs formula on babies' development. The bit about cells was interesting, but otherwise I feel like you wasted my time.

    August 12, 2019
    Reply
  89. Tinka Like AngelOK said:

    I rather milk my oats 🤷🏼‍♀️

    August 12, 2019
    Reply
  90. BLINKDARA said:

    I hate milk.

    August 13, 2019
    Reply
  91. BmnGameBoy said:

    Reindeer of the arctic circle🎶 sounds like a line in a song

    August 14, 2019
    Reply
  92. • Jen Dog • said:

    “Why do humans drink so much milk”
    Me: I don’t

    August 17, 2019
    Reply
  93. mexicano soy said:

    tetassss

    August 17, 2019
    Reply
  94. Huitzilli said:

    I don't Drink cows milk. 🐄 🍼 I'm not a cow. Lol

    August 18, 2019
    Reply
  95. Chad Patterson said:

    I ❤️whole milk

    August 25, 2019
    Reply
  96. Dream Cardigan said:

    Male cats?!?

    August 26, 2019
    Reply
  97. Theodore Bugsby said:

    Then, if milk supposedly supplies most of the needed calcium the more one drinks milk more chances there are to get osteoporosis?

    August 27, 2019
    Reply
  98. aidan harrison said:

    From sheeps ?

    August 28, 2019
    Reply
  99. aidan harrison said:

    The fats in milk are not " added "

    August 28, 2019
    Reply
  100. True Sagittarius said:

    Not gonna lie, I thought the video would be talking about the tits, disappointed.

    September 3, 2019
    Reply

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