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Is there blood in milk?

Whether there is blood in milk is a common question for many consumers. Milk is a staple food product that most people consume on a regular basis. Naturally, people want to know if the milk they are drinking contains any blood.

The short answer is that while there can be traces of blood in milk, it is not a health concern. Modern dairy farming practices and milk processing standards ensure that any blood in milk occurs at extremely low levels that are not a risk to human health.

Where does milk come from?

To understand if and why blood may end up in milk, it is important to first look at where milk comes from. Milk is produced by dairy cows and is intended to provide nutrition for their calves.

Cows must give birth to a calf in order to start producing milk. The cow’s udder contains small sacs called alveoli that produce milk in response to hormones released when the cow gives birth.

The udder is filled with blood vessels to supply the alveoli with blood and collect the milk. So while the purpose of the udder is to produce milk, it does contain blood as part of its anatomy.

How does blood get into milk?

Given the presence of blood vessels in the udder, there are a few ways that traces of blood may end up in the milk:

Damage to the udder: If the udder becomes injured or inflamed from impacts, chapping, infections, etc., it can damage blood vessels and cause bleeding into the milk ducts. Even small cuts or cracks in the teat can allow tiny amounts of blood.

Mastitis: This is an infection of the mammary glands that causes inflammation. The swelling can rupture blood vessels, releasing blood into the milk.

Milk letdown: When milking first begins, the release of oxytocin and relaxin cause the tiny muscles around the alveoli to contract and push the milk out. This milk letdown process can sometimes damage capillaries and introduce traces of blood.

Age and hormones: Older cows and those with changing hormone levels after calving are more prone to udder bleeding and bloody milk.

So in reality, the presence of blood or blood spots in milk is not completely abnormal or unexpected when considering the anatomy and physiology of milk production. But modern dairy farms follow best practices to minimize this.

Dairy farm practices to limit blood in milk

Reputable dairy farms follow certain guidelines to ensure high quality milk with very minimal blood:

– Careful monitoring of udder health. Mastitis and injuries are treated quickly.

– Milking equipment is kept clean and well-maintained to avoid cuts or abrasions during milking.

– Udders are cleaned and stripped prior to milking to remove any abnormal milk.

– The milk is examined during milking for visual abnormalities. Bloody or stringy milk may be diverted away from the main milk supply.

– Cooling milk quickly after milking prevents any blood from replicating.

– Administering oxytocin makes letdown more gentle and less likely to damage blood vessels.

When these best practices are followed consistently, the occurrence of blood in the milked supply can be greatly reduced. But despite best efforts, tiny traces may still enter milk at times.

How milk processing removes blood

The dairy industry follows very stringent standards for processing raw milk from farms into products for consumers. Here are some steps that remove any traces of blood:

Separation and skimming: Raw milk is spun in a centrifuge which uses density differences to separate milk fats from proteins and blood. The blood particles rise and are skimmed off.

Homogenization: Milk fat globules are broken into smaller sizes which distributes any remaining traces of blood into tinier particles.

Pasteurization: Heating milk to at least 145°F for 30 minutes kills any blood-borne bacteria and deactivates blood enzymes.

Additional filters: Milk may pass through additional filters that catch any particles bigger than blood traces.

Using this multi-step approach, it is highly unlikely that any amount of blood poses a health risk by the time milk makes it to the grocery store fridge. Tiny amounts well below 1% may remain, but are harmless at such levels.

How much blood is allowed in milk?

The dairy industry adheres to extremely strict standards for the maximum allowable level of blood and all other impurities in milk:

– The FDA Pasteurized Milk Ordinance allows no more than 10 million somatic cells per milliliter. Somatic cells include white blood cells that enter milk through bleeding.

– The European Union standards allow a maximum of 400,000 somatic cells per mL.

– Standards by the Dairy Practices Council in North America cite 100,000 cells/mL as the maximum somatic cell count for high quality.

– For direct comparison, normal human blood contains 4 to 10 million red blood cells per mL.

So these maximum somatic cell counts show that any blood content in processed milk is minuscule in comparison to pure blood. Such tiny traces have no negative health impacts.

Regulator Maximum somatic cell count per mL
FDA 10 million
European Union 400,000
Dairy Practices Council 100,000

Does milk with blood get recalled?

In very rare cases, higher levels of blood may be found that warrant recalls:

– In 2011, a dairy in New York did issue a limited recall after a farm inspection detected elevated blood levels above the FDA limit in some batches. However, the dairy maintained this was an isolated event and no illnesses occurred.

– In 2016, milk from an Oregon dairy was recalled when testing found bovine blood DNA indicative of milk mixing directly with bloody fluids. An equipment malfunction was suspected.

– Most recently in 2019, cartons of Fairlife milk were pulled from store shelves after an animal rights group released video of workers abusing cows – some showing visible blood in the milk. However Fairlife stated that the milk met all FDA standards.

So while occasional recalls do occur if blood content is above normal, these are extremely isolated incidents. The vast majority of milk products on the market adhere to rigorous standards and do not contain concerning levels of blood.

Does milk have pus or blood cells?

Due to the information on somatic cell counts, some consumers become concerned about pus or blood cells in milk. Here are the facts:

– Somatic cell counts consist of 75-85% white blood cells such as lymphocytes and neutrophils, with only a small portion of red blood cells.

– Neutrophils and macrophages are increased as part of the cow’s natural immune response to fight infection. They are not “pus cells” as is sometimes claimed.

– The number of actual blood cells in milk is minimal compared to the overall volume. Plus these cells are broken down during processing.

– Homogenization splits apart any cells present in the milk anyway.

So the presence of these immune cells in small amounts is a normal bovine body process and not a sign of poor milk quality. The number of cells is tightly regulated to very low thresholds.

Can milk cause blood clots or problems?

For most people, drinking milk does not pose an increased risk for blood clotting or other health issues. However, some individuals may need to moderate their milk intake:

– People with lactose intolerance can experience inflammation after drinking milk, but this does not make clots more likely.

– There are very rare milk allergies that cause blood histamine levels to rise, resulting in agonizing headaches, nausea, and hypertension. This temporary reaction is not the same as clotting though.

– In people with existing cardiovascular issues, there is some research showing milk fats slightly increase risk factors for clotting like inflammation and cholesterol. But this is inconclusive and mainly applies to those already at risk.

So for the majority of healthy individuals, standard milk consumption should not be a concern in terms of blood issues or clotting. Those with existing clotting disorders or milk allergies may need to exercise more caution and limit intake after discussing with a doctor.

Does chocolate milk have blood?

Chocolate milk starts off with conventional pasteurized, homogenized white milk. The chocolate syrup is then added into this milk base. So any traces of blood that may have been present originally would remain after the addition of chocolate flavoring.

However, the chocolate and sugar content have no relation to blood levels. Chocolate milk has the same extremely low allowable somatic cell counts from bleeding as regular white milk. Any blood content would be negligible and pose no health problems.

Chocolate milk blood levels:

– Adheres to the same FDA standard of Does raw milk have more blood?

Raw milk refers to unpasteurized, unprocessed milk straight from a cow’s udder compared to store-bought pasteurized milk. Does raw milk naturally contain more blood cells or particles?

There are a few reasons why raw milk may have slightly more visible traces of blood:

– Lacks the heat of pasteurization to deactivate enzymes in any blood present.

– Does not undergo separation, skimming, homogenization, and filtration like processed milk. Any blood remains intact.

– May come straight from cows with mastitis infections or udder damage that caused bleeding.

– Bacteria in raw milk can multiply faster when blood nutrients are available.

However, most raw milk still comes from healthy cows using sanitary practices, and significant visible blood would not be common. Any difference in blood traces between raw vs pasteurized milk is minimal at most. Both contain only minuscule amounts that pose no health risks.

Raw vs pasteurized milk blood levels:

Milk Type Typical Blood Content
Raw milk 10-150 white blood cells per mL
Pasteurized milk 10-80 white blood cells per mL

So while raw milk standards are less stringent when it comes to blood cell counts, the overall blood content remains very low in either form of milk.

What does blood in milk look like?

When milk contains higher-than-normal traces of blood, here are some of the visual signs:

– Streaks or swirls of pink, red, brown, or grey

– Small flecks or clumps of red blood cells clustered together

– A rusty, bloody, or salty taste

– Increased viscosity or clumpiness from blood proteins

– Clear yellow serum if plasma separates from clotted blood

– Layer of bloody cream at milk surface when left sitting

However, these more obvious blood characteristics only occur when levels are elevated above typical standards. Blood content in normal milk that has undergone proper processing will never have these strong visual indicators.


In summary, while there are anatomical and biological reasons that trace amounts of cow’s blood can end up in milk, it is not a health concern for consumers. Rigorous standards limit blood content to extremely low allowable somatic cell counts in dairy herds. And extensive processing removes any stray cells or particles that may be present.

The tiny residual traces have no negative or dangerous impacts on health and do not present any increased risk for blood clotting, allergic reactions, or other problems. Consumers can be confident that retail milk has been treated to create a staple beverage free of any worrisome levels of blood. So unless you have an underlying condition or milk allergy, you can keep enjoying your cereal, lattes, and chocolate milk without worry.