A greenish/blue tinge is apparently quite normal.
Here's a quote from the LLL website:
The color of human milk can vary. Colostrum is generally yellow to yellow- orange. The transition from colostrum to mature milk can take about two weeks to complete. During that time, the color changes gradually to a bluish white color. However, the color of mature milk may change because of mother's diet or medications. Food dyes used in carbonated sodas, fruit drinks, and gelatin desserts have been associated with milk that is pink or pinkish orange. Greenish milk has been linked to consuming green- colored sports beverages, seaweed, or large amounts of green vegetables. One woman consuming a certain prescription medication reported black milk. Frozen milk may look yellowish.
I think there's bound to be some variation depending on which breast you used last. I don't think you have reason to panic.