of factors can cause cabbage to turn black. Fruits and vegetables have natural colour pigments -- these pigments can react to a variety of factors such as acidity in tomato sauce, heat, cooper or aluminium cookware and/or utensils. Also fruits and vegetables can have lower level of pigments that only show up after cooking. For example, green cabbage can turn a very dark purple/black. In some incidences cabbage can also turn pink. If the cabbage you froze was fresh and in good condition prior to blanching and freezing your cabbage rolls are safe to eat. If the cabbage was stored in your refrigerator for longer than 2 weeks prior to blanching and freezing, I would recommend discarding the cabbage rolls. Old cabbage can turn dark brown/rusty. Hi!  Can I thawed spaghetti sauce (with boeuf and other grounded meats) or frozen chicken broth directly from the freezer to the stove?  I did that several times and everyting thaws quite fast in a pan heated at medium.  Thanks! Yes,  you can do that as long as you achieve the proper temperature to heat up the spaghetti sauce or the chicken broth and make sure that they are completely thawed and the heat is evenly spreaded throughout the food.  It should be consumed without delays I cooked mac&cheese.  It was in the hotcase at work for three hours at a temp. of 150F. How long is this good for? Can this be refrigerated and reheated again? How long is it good for refrigerated?