Breast milk is blue

Hey mommas. I don’t breastfeed but I pump and feed my baby breast milk in a bottle. She’s 6 months already, but noticed my milk is turning blue. All of my milk is blue no white at all. I do give her formula as well I would do breast milk all day and formula at night but my milk supply has been low so now it’s the other way around. I changed pumps bc I thought that maybe the cause but idk what to do. I pump no white milk at all