What Is Milk Protein? How can it be vegan?

Kathleen Nay at Perfect Day


Milk is defined by the U.S. federal government as the lacteal secretion obtained by milking one or more healthy cows.4 Protein is a relatively small component of whole milk; on average, fluid milk from cows is about 88% water, 5% lactose, 3% milkfat, 3% protein, and less than 1% minerals (although exact composition depends on the cow’s breed, nutrition, and stage of lactation).5 However, only a miniscule amount of allergen is needed to trigger an immune response in people with allergies. 


There are six major proteins found in cow's milk: four caseins (alpha-s1-, alpha-s2-, beta-, and kappa-casein) and two whey proteins (alpha-lactalbumin and beta-lactoglobulin). Both casein and whey protein groups are characterized as allergenic.6 

Perfect Day is developing animal-free versions of all six major milk proteins, but the first protein we have commercialized for use by food makers is non-animal beta-lactoglobulin, a whey protein. One of our long-term research goals is to identify ways of reducing the allergenicity of dairy proteinshowever, this research will take some time. For now, Perfect Day proteins cannot be considered allergen-free. 

Perfect Day is committed to transparency and consumer safety, and we require the same from our partners, including N!CK'S. We're required to take all three of these steps: 

  1. Clearly indicate “Contains Milk Allergen” or “Contains: Milk Protein” on the front of product packaging. 
  2. Include “non-animal whey protein” in the ingredients list on the product packaging, in compliance with FALCPA. 
  3. Include “Contains: Milk Allergen” or “Contains: Milk Protein” in bold type following the ingredients list on the back of product packaging, in compliance with FALCPA. 

We are taking additional steps to work with leading food allergy organizations and individuals to help shape allergen education in order to protect consumers. 



For the first time in the history of milk consumption, cow's milk proteins are being produced in an organism other than a cowFermentation enables us to make highly nutritious, tasty, lactose-free dairy products without relying on animals. Our mission is to create a kinder, greener tomorrow for animals and our planet, but our number one commitment is to our community today. That means we need to be very clear about who can and cannot consume products made with Perfect Day ingredients. 


1. Food Allergy Research & Education (FARE). (n.d.). What is a food allergy? https://www.foodallergy.org/resources/what-food-allergy/
2. Mayo Clinic. (n.d.). Anaphylaxis. https://www.mayoclinic.org/diseases-conditions/anaphylaxis/symptoms-causes/syc-20351468 

3. Castle, Jill. (2020, July 16)guide to the most common food allergies. Verywell Health. https://www.verywellhealth.com/the-most-common-food-allergies-1324134#milk-allergy

4. U.S. Food and Drug Administration. (2020). CFR - Code of Federal Regulations Title 21, Section 131.110
5. Milk Facts. (n.d.). Milk composition. http://www.milkfacts.info/Milk%20Composition/Milk%20Composition%20Page.html

6. Mills, Clare et al. (2004). Processing approaches to reducing allergenicity in proteins. In R.Y. Yada (Ed.), Proteins in food processing (pp. 396–418). Woodhead Publishing. doi.org/10.1533/9781855738379.2.396 

7. Food Allergy Research & Education (FARE). (n.d.). How to read a food label. https://www.foodallergy.org/resources/how-read-food-label 
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