Lots of good answers here, and opposing opinions too. Food for thought (no pun intended). Here are some additional factors that have not been mentioned, yet play a role in the debate:
1). The color of foods that are in your refrigerator, affect the amount of energy required to maintain their set temperature. Consider this: Your refrigerator is well-insulated, to slow the rate of heat transfer from the area surrounding the fridge, to the area within the fridge. If you were a reptile, with the ability to see infrared heat energy (very useful for locating warm-bodied prey) you might be able to see a greater amount of red glow outside of the fridge, as opposed to inside it. The point is this; the "red glow" or heat energy, is continually flowing from the higher level source (outside of fridge) to the lower level destination (inside of fridge). Now, if you happen to be an intelligent, infrared seeing reptile, you might also be aware that the infrared energy that flows through the insulation of the fridge, subsequently bathes the food items with a warming glow. However, the prudent reptile is very much aware that "clear" fridge items (such as a bottle of spring water) allow much of the red glow to pass through them, without absorbing a significant percentage. In contrast, dark colored pork chops absorb nearly all of the infrared glow that reaches them; allowing very little of it to pass through. 762
For this reason, dark colored foods absorb heat energy at a faster rate, while stored in your fridge, than do light colored foods (even inside your fridge). 2). Bacterial decomposition... Lets face it. The reason we store our foods in a refrigerator, is to lower their temperature for the purpose of slowing their rate of decomposition. As bacteria break food matter down into waste product, their busy little bodies generate heat energy. Consider a compost heap (composed of biodegradable matter). Bacteria, along with a host of other organisms, essentially "oxidize" the organic matter in their bodies, which, in turn, produces heat that can be easily observed as a warming effect on the entire heap. Although our food products are decomposing more slowly in our refrigerator, they are indeed decomposing, and heat is being generated within. Thus, a refrigerator that is full of food, tends to "self generate" heat at a greater rate than a fridge that has very little food in it; thereby requiring more cooling to compensate for those pesky little bacteria that were not invited to the party. Question: Do dark colored foods tend to undergo temperature cycles of greater variation, while stored in your refrigerator; thus permitting increased bacterial growth within a given period of time, and ultimately "spoiling" sooner than light-colored foods? (If you can correctly answer this, you may well be a reptilian genius!) Ha. 1022