Can Eating Expired Cake Make You Sick?
Different people have different takes on the whole idea of what foods are safe to eat and what ones are not. Some will religiously check the package dates, preferring to toss the whole thing out rather than take the slightest risk, while others will gleefully defy those dates and film their expired food eat-a-thons for social media.
Although there may be some area between the two poles where many of us would prefer to remain, the USDA itself actually weighs in closer to the zero food waste side of the argument. As it points out, the bacteria that cause food to spoil are not the same as the kind that causes foodborne illness. That being said, some foods definitely don't last long after you've brought them home from the store, and nobody likes spoiled, moldy raspberries or milk that's gone sour. Other foods, such as cake, will tend to keep for quite a bit longer. Whether you buy your cake in the store or make it from scratch, you might have more time to enjoy it than you'd think.
Cake mix is pretty shelf-stable stuff
The USDA says cake mix can be stored for up to 18 months before opening without a noticeable dropoff in quality. After that date, you may experience cakes that won't rise properly or possibly have a rancid flavor or odor if the mix contains any type of fat. Even in such a case, the mix is unlikely to make you ill unless it exhibits obvious signs of spoilage or contamination. Then again, if you open a box of cake mix to find mold, insects, or rodent feces, why would you want to use it anyway?
One rumor that has been making the rounds since the mid-00s, at least, involves a person who was hospitalized due to being exposed to deadly mold found inside a box of expired pancake mix, something which was subsequently extrapolated to apply to baking mixes of all kinds. The rumor, however, appears to be unfounded and food safety experts have said that food molds need moisture in order to grow. If your boxed mix is damp when you open it, this definitely indicates a problem of some sort (a leak in your pipes, perhaps?) and the product should probably be tossed straight in the trash. As long as the cake mix is as dry as the day it was packaged, though, mold is unlikely to be an issue.
Certain types of pre-made cakes may pose a threat
What about a cake that's already been baked, though? Is that something that's going to make you sick once it's no longer fresh? Again, the drop-off is more likely to be in food quality than safety. Cake will be at its freshest and best tasting if eaten within a week, but will last a few days longer if you stick it in the fridge and longer still if frozen. (Frozen foods, as long as they stay frozen, will never actually expire, but after 6 months or so in cold storage, they may never quite regain their former glory.) Even when cake grows stale, though, it's still perfectly okay to eat or at least to re-purpose in trifles, cake pops, or crumb toppings.
Where you might run into trouble eating cake that's past its prime is if that cake has a custard filling or meringue topping since the eggs in these can allow dangerous bacteria to breed. Cheesecake, too, is something that has the potential to be harmful if it's not kept refrigerated, or, even then, if it stays in the fridge for over a week. Cream cheese can be a potential breeding ground for listeria, so it's best to freeze any cheesecake you won't consume straight away. As a bonus, not only will freezing keep your cakes contamination-free, but cheesecake and any kind of cake actually taste delicious straight out of the freezer.
Snack cakes, however, are a different story
One thing that differentiates packaged snack cakes from either homemade or bakery cakes is the fact that they typically contain a higher level of preservatives so tend to have a longer shelf life, as well. Take the Twinkie, for example. While these products don't actually live up to the myth that says they'll stay fresh for up to 100 years, the manufacturer claims that they're guaranteed to be fresh (or as fresh as a Twinkie gets) for 65 days from the time they're baked or 45 days from the time they hit store shelves. Even once "expired," many snack cakes are still safe to eat to the point where some may be sold by salvage stores and bakery outlets such as Entenmann's.
Snack cakes, including the legendarily long-lasting Twinkie with its lengthy list of ingredients, still won't last forever, though. While anecdotal accounts speak of people eating them many months later and finding them to taste okay, a man who stored a box of Twinkies in his basement for 8 years and then took a bite found the cakes to be less than fresh. In fact, so grossed out was he by their off-putting flavor, texture, and appearance that he donated the remaining snacks to science and further studies found that one of the Twinkies did, in fact, contain a mold called Cladosporium. Although this fungus certainly makes for a nasty surprise to find in place of cream filling, it generally isn't harmful to humans