The belief that yucky things lurk in the depths of dark-colored liquids is a widespread food fear. Blood is generally considered icky, so schoolchildren regularly horrify each other with whispered claims that the milk used in chocolate milk is just swimming with the stuff. Now that prepared coffee beverages are making it to the supermarket shelves we’re seeing this particular tale expand to include those products, thereby broadening the age range of this rumor’s audience.
(The belief that cow’s blood is to be scrupulously avoided at all costs is suspended in our dealings with meat products. No one recoils in horror at the thought that a steak or a hamburger contains cow’s blood — our beef with ingesting blood apparently stops at the fork.)
In the U.S., the Food and Drug Administration oversees the safety of food products. Stringent standards have been established for all milk destined for consumers, including the chocolate variety. It is telling that this agency’s specifications contain no allowances for the use of blood-contaminated milk. Milk products (and other foodstuffs) that do not meet the agency’s criteria do not gain FDA approval and thus cannot be sold to consumers.
In other words, the “cow’s blood in the chocolate milk” story doesn’t fly any better than a cow would.
A similar version of this rumor which claimed to show “what cow’s milk looks like before they whiten it” was circulated on social media in 2017:
Although this image is genuine, it doesn’t show the “real color of cow’s milk” before it gets whitened. This image was taken from a 2013 video from the “Funky Farmer”, and it shows the milk produced by a cow that had recently given birth.
In fact, farmer Richard Cornock explicitly states in the following video that the red color doesn’t happen very often, and that the pictured milk is “not fit for human consumption”:
“In this case on the left we have a lot of blood in the milk. It doesn’t happen often like that but occasionally you get blood in the milk because maybe there’s a blood vessel burst in the udder or something. That always comes right in the end. Might take a week of milking. But as you can see it’s not fit for human consumption. So we have to keep that out at the end.”
Chenoweth, Doral. “Cat, Dog Meat Rumors Should Be Put to Rest.”
The Columbus Dispatch. 7 September 1995 (Features; p. 16).