Cow's milk can appear slightly yellowish due to the presence of a pigment called beta-carotene. Beta-carotene is a natural compound found in the grasses and plants that cows consume as part of their diet.
When cows eat grass, particularly fresh green grass, they ingest beta-carotene, which gets transferred to their milk.
Beta-carotene is a type of carotenoid, a pigment responsible for the orange, yellow, and red colours found in many fruits and vegetables. In the case of cow's milk, the beta-carotene present in the grass can tint the milk slightly yellow, giving it a cream or off-white colour.
The intensity of the yellowish hue can vary depending on factors such as the cow's diet, the season (since grass composition can change), and breed. Additionally, milk processing methods, such as pasteurisation and homogenisation, can affect the appearance of the milk.
It's important to note that the yellowish tint of cow's milk due to beta-carotene is entirely natural and does not indicate any health concerns. Beta-carotene is a precursor to vitamin A, an essential nutrient for human health, and its presence in milk can contribute to its nutritional value.