Newly-bought lamb shank turned blueish-green while marinating; safe or discard? Cooking

Hello /r/Cooking,

I was preparing a roast lamb shank dish tonight. These were the steps I had taken regarding the shank itself:

1. Remove two shanks from refrigerator (purchased this morning and left in fridge for 12 hours). Sealed in vacuum-pack, expiration date August 6.

2. Opened pack, both lamb shanks had good smell, patted down with towel. Added 1tsp fennel seed and rosemary plus 1 clove of minced garlic, 1tbsp of salt, and 2tsp of pepper.

3. Left to rest at room temperature for 1 hour, covered, as called for by recipe.

When I opened the lamb shanks to place them in their roasting sauce, the tendon fibers (not the muscle itself) had turned a blueish-green color. Are these lamb shanks still safe to eat?

I have put them in the oven, but will discard if the answer is no.

Submitted July 17, 2017 at 08:25AM by shaanxiprovince http://ift.tt/2utuWQf Cooking