Though the days of cooking, mountains of dishes, and hours of food coma gave you doubts, you make it through Thanksgiving. If your Thanksgiving is like mine, your family of vultures only made a tiny dent in the bounty, leaving you with the best part of all: leftovers. Some things, like chili, pasta sauce, and fine wine are known to taste better as they age, but how does turkey fare? To answer that question, we delve into the science and see how cooked poultry spoils, and how long you can safely brown-bag those homemade turkey sandwiches.
As we've mentioned before, part of the reason we cook food is to remove the dangerous bacteria that can quickly spoil our meals. Unfortunately, even after we cook our food, it's still quite vulnerable to re-infection with food-spoiling bacteria. Some bacteria even survive the cooking process altogether, leaving cooked meats contaminated before they even go into the fridge.
Know thy enemy
When it comes to food spoilage, not all bacteria are created equal. Almost everything around us is covered in bacteria. But don't panic—only a small percentage can ruin your day, and many of them are actually beneficial. When it comes to spoiled turkey leftovers, there are actually only two bugs you have to worry about: Aeromonas hydrophila and Pseudomonas putida.
These two bacteria are common household offenders that latch onto cooked food and—in large quantities—can make your food spoil.
Be aware of your surroundings
Bacteria are everywhere—a clean kitchen included. No matter how hard you may try or how spotless it might look, keeping your kitchen sterile is impossible. Aeromonas hydrophila in particularly is pesky: It can be found on utensils, "clean" plates, counters, and other surfaces.
Now, knowing that bacteria are everywhere is key to a better understanding of food spoilage, but don't panic and stock up on antibacterial cleaning supplies. Just relax and accept the inevitable. Recent studies have shown that antibacterial soap and regular old soap are equally efficient at keeping bacteria at bay. So don't be fooled: Just because it says "anti-bacterial" on the bottle does not mean that it will necessarily rid you of each and every bacterium.
As it turns out, part of the reason why Aeromonas hydrophila is so prevalent and difficult to eradicate is that it is found en masse inside the average kitchen tap. If you know some Greek, you know that the hydrophila is a dead giveaway here: It roughly translates to "water lover." In other words, even after you remove all of the bacteria from your carving knife, the final rinse just adds new Aeromonas hydrophila. The same thing happens to everything that you clean in the sink: cutting boards, serving forks, and so on. All of these things are contaminated with the spoiling bacteria, and can easily contaminate the turkey after it's been cooked.
It’s pretty much impossible to avoid bacteria in your leftovers, but we do have a pretty handy weapon in our corner: the fridge. Fridges don't solve the problem, but they do buy us some time—time we can use to finish off those Turkey Day leftovers. At fridge temperatures (around 37°F), both Aeromonas and Pseudomonas still flourish, albeit at a much slower rate. Just how much slower depends on the quality of the refrigerator.
When the fridge temperature remains steady at 40°F, it takes about six days for enough bacteria to grow on the leftovers to start smelling and tasting spoiled. This is the best-case scenario; a perfect fridge will keep the leftovers a-ok until the Wednesday after Thanksgiving. In reality, as we well know, most fridges are far from perfect. Temperature deviations inside the fridge can seriously shorten the keep-fresh period from six to only two days, which can mean wasting half the bird.
So, what can you do to maximize the lifespan of your leftovers? In principle, the goal should be to minimize exposure to bacteria and then provide ideal cooling conditions once the turkey is off the table and in the fridge.
To minimize bacterial contamination, cutting boards and utensils should be cleaned in the dishwasher on the sanitation cycle, or hand-washed in hot water to avoid recontamination from the bacteria that hangs out in your kitchen taps.
Investing in a good refrigerator can also extend the lifetime of your precious turkey scraps, potentially doubling or tripling the period when your leftovers can still be safely consumed. Check out our refrigerator reviews to find the best-performing fridges and keep your family safe from turkey-and-bacteria sandwiches.
Contributing Author: Ethan Wolff-Mann
Photos by Nathan Reading CC-BY-SA-3.0, adrigu CC-BY-SA-3.0, Julia Frost CC-BY-SA-3.0, Bénédicte Jourdier CC-BY-SA-3.0, shaughn halls CC-BY-SA-3.0
Citation: Toule, G. et al., J. Hyg., Camb., 1978, 81, pp. 161-169