Cracking open a perfect-looking egg only to find an unsightly blood spot can be alarming.
Many assume that these eggs aren’t safe to eat.
Not only can this assumption ruin your breakfast, but throwing out eggs with blood spots can contribute to food waste as well.
This article explains why blood spots occur in eggs and whether they’re safe to eat.
Why Do Some Eggs Have Blood Spots?
Blood spots are droplets of blood sometimes found on the surface of egg yolks.
Although egg producers consider them a defect, blood spots form naturally during the egg-laying cycle in some hens.
Contrary to popular belief, they do not indicate that an egg has been fertilized.
Blood spots are the result of the rupturing of tiny blood vessels in the hen’s ovaries or oviduct — the tube through which eggs pass from the ovaries to the outside world (1Trusted Source).
A hen’s ovaries are full of tiny blood vessels — and occasionally one will break during the egg-laying process.
When the spot is connected to the yolk, the bleeding most likely occurred in the ovary when the egg was released from the follicle.
The follicle is a fluid-filled sac that contains several blood vessels. It may burst during the egg-laying process, and if any blood vessels rupture, blood can deposit on the egg yolk.
Blood spots can also occur in the egg white, which means that the bleeding occurred after the egg was released into the oviduct.
Another type of spot found in egg yolks and whites are meat spots. Unlike blood spots, meat spots appear on the egg white as brown, red, or white deposits.
Meat spots are most commonly found in the egg white and typically formed from pieces of tissue picked up by the egg when passing through the oviduct.
Are Blood Spots Common?
Finding an egg with a blood spot in its yolk is pretty uncommon.
In fact, the frequency of blood and meat spots is less than 1% in all eggs laid in commercial factories (2Trusted Source).
Egg color is a factor in the occurrence of blood spots.
The incidence of these spots is around 18% in hens that lay brown eggs, compared to only 0.5% in white eggs (2Trusted Source).
Additionally, older hens at the end of their egg-laying cycle and younger hens who just began laying eggs tend to lay more eggs containing blood spots.
Poor nutrition — including a lack of vitamin A and vitamin D — and stress can also increase the chances.
Safe to Eat?
It’s understandable that you may be concerned about eating eggs with blood spots.
However, according to agencies like the United States Department of Agriculture (USDA) and the Egg Safety Board, eggs with blood spots are safe to eat as long as the egg is properly cooked (3).
Consuming raw or undercooked eggs, whether they contain blood spots or not, increases your risk of salmonellosis — infection with Salmonella bacteria that can lead to diarrhea, fever, and abdominal cramps (4Trusted Source).
Also note that eggs with whites that are tinted pink, green, or red may contain bacteria that cause spoilage and should be discarded (5).