Uncovered Raw Meat or Milk in Fridge

Question

I believe the harm in leaving raw meat uncovered in the fridge is that more bacteria will enter, more oxygen will enter (causing faster bacteria multiplication), and more water will escape (causing dryness which probably slows bacteria multiplication, but toughens the meat, so let's consider dryness to be bad; I'm not making beef jerky). Please ignore the stinky odors that escape; just consider the quality of that one uncovered piece of meat after we eventually cook it.

How much faster will the food spoil (percentage, compared to the same meat wrapped in plastic wrap)? I imagine that meat with skin, like a whole chicken, is not effected as much as meat without skin, like a bare chicken breast, and that ground meat would be effected the most. I wish I had some data to convince my roommate to cover his meat; is there any research on this? Feel free to answer this for milk instead if there is more research for it.

Answer 1

There is no practical difference in spoilage time for wrapped versus unwrapped. Spoilage is a factor pretty much of temperature, since in practice, all foods have pathogens present which can breed.

Assuming your refrigerator is free of insects, dogs and similar macro-fauna, wrapping is to prevent odors from going from one food to another, drying, or cross-contamination of one food by another through drips or splashing. Now, outside of a refrigerator, where ants, flies, and so on are abundant, wrapping also provides a physical barrier to prevent infestation, but the body of the refrigerator already does that.

In fact, in some rare occasions, you may wish to specifically refrigerate your meat unwrapped: for example, after brining a turkey, refrigerating it for 24 hours unwrapped will permit the skin to dry out, and permit a more crispy result.

Answer 2

Only a half answer, but particularly with meat, you're really risking contaminating other things in your fridge. It's dangerous for that reason alone, so I wouldn't even bother worrying about whether the meat itself spoils faster, since I'd be worried about everything else in the fridge.

Answer 3

Your initial assessment sounds pretty dead on. OFCOURSE sealing foods will slow spoiling. Your concern about bacteria and such needing oxygen to breed is certainly correct - for for all micro-organisms, but most.

As far as the argunent made that the bacteria is always present internally in meat is only part true. first, it makes a world of difference whether we're talking about cooked or raw meats.

in the case of cooked meat, assume that after you properly cooked it there is no living bacteria and it. That means that for it to spoil, it needs to be exposed to bacteria from the external environment. A lot of sources exist to do this such as, handling it, breathing on it, siliva exposure to contaminants in the air in general, exposure to other food products, etc.

so it's pretty clear that proper storage that's not open and exposed will slow spoiling, especially when you add in the oxygenation effect. that said,if you wash food before sealing it you certainly want to try it off since moisture is quite the catalyst for breading micro-organisims.

in the case of raw meat that potentially contains live bacteria and parasites in it, the type of meat makes a pretty big difference. that's why we thoroughly cook poultry and pork but not necessarily beef.

rather than believe me, since others seem to disagree with what I just said, here's a pretty good link with professional advice on the matter.

http://www.foodsafetysite.com/educators/competencies/general/spoilage/spg1.html