For many of us, one of the most upsetting moments of adulthood was learning that the five-second rule doesn't exactly hold up (more on that below). Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Bravo To get to the bottom of other widely believed food rules — and find out what's true and what's bogus according to the agency that regulates food safety — I reached out to an expert therein. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Warner Bros. Peter Cassell is a spokesperson for the FDA, where he advises experts and media outlets on food safety policies, outbreaks, and recalls. To ease your eating worries, here's the lowdown on eight food safety questions you've likely had at one point in your life: Food "Rule" #1: It's unsafe to drink milk past its sell-by date, even if it's just a day or two. Melissabrock1 / Getty Images / Via gettyimages.com The low-down: Not necessarily.As Cassell explains, "Drinking milk a day or two after the milk’s expiration date (otherwise known as the sell-by date) may not be a safety issue but may be more of a taste issue." That said, drinking milk any amount of time past its expiration date "does increase the risk of developing food-borne illness from bacteria that might have grown," says Cassell. But unless you're part of a particularly immunocompromised population (elderly people, pregnant women, and young children would fall into that category), and if your milk is just a few days past its expiration date, then you're probably good to go. Just give it a whiff before you drink it. Food "Rule" #2: You shouldn't drink from a cup of water that has been left sitting out overnight. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Imagine Entertainment The low-down: False.Your water might taste a little funny if it's been sitting on your bedside table overnight, but "it is still perfectly fine to drink." After all, Cassell says, water itself has no ingredients that would make it go bad. Food "Rule" #3: White discoloration on a chocolate bar means the chocolate has gone bad. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Jersey Films The low-down: False.If you were thinking of throwing out that discolored bar of chocolate you just unwrapped, think again. A white or grayish film on the surface of your chocolate might look alarming, but it's most likely just a fat bloom. "This occurs when cocoa butter fats separate from the cocoa. It’s completely normal and safe to eat," says Cassell. Food "Rule" #4: Butter should be stored in the fridge, not at room temperature in a butter dish. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Biem via Wired / Via wired.com The low-down: True.If your household is in the habit of leaving a butter dish out in room temperature, maybe you should rethink the practice. According to Cassell, leaving your butter in warmer temperatures puts it at risk of "increased rates of oxidative rancidity, which leads to the more rapid development of an unusual or unpleasant flavor." On the other hand, refrigeration both preserves the shelf life of butter and "reduces the growth rates of spoilage microbes which might be present." So, refrigerate your butter, and if you want warm, spreadable butter, try using a serrated warming butter knife. Food "Rule" #5: All fruit and vegetables should be washed before eating. Luckybusiness / Getty Images / Via gettyimages.com The low-down: Unless it's marked "prewashed" or "ready to eat," this is true.All produce and fruit can be contaminated in many ways: During the growing phase, fruits and veggies could be contaminated by animals, harmful substances in the soil or water, or poor hygiene among workers — not to mention all those pesticides used during cultivation. According to one USDA test, nearly 70% of samples of 48 types of conventionally grown produce were found to be contaminated with pesticide residues. So, unless your fresh produce and fruit is marked "prewashed" or "ready to eat," be sure to give it a good wash before prepping or eating it — especially if it's one of the dirty dozen. Food "Rule" #6: Raw eggs will make you sick. Lindasphotography / Getty Images / Via gettyimages.com The low-down: Not necessarily, BUT you can’t tell from the outer shell or inside of the egg if it is contaminated, so always refrigerate eggs and cook until the yolk is firm. Raw eggs have a chance of being contaminated with harmful bacteria such as salmonella, but since bacteria are microscopic, you won't be able to just weed the bad eggs out. The best practice is to refrigerate, handle, and cook eggs properly, says Cassell. Cook eggs until both the yolk and white are firm and cook any egg dishes until they are at an internal temperature of 160°F or hotter. Food "Rule" #7: You shouldn't double-dip. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Sony Pictures Television The low-down: True! Double-dipping can spread harmful bacteria and viruses and is especially sketchy because a person doesn’t have to be visibly sick or sick at all to pass on germs. "It’s best to put dip on your own plate so that you can enjoy it without spreading germs to others," says Cassell. "If you know that you are ill, it may be a good idea to stay away from communal snacks or foods altogether." Food "Rule" #8: If you bring a homemade salad to work, you should refrigerate it immediately. Keeping it at room temperature will make it go bad by lunchtime. Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF Tap to play or pause GIF E! The low-down: True.It all comes down to what kinds of ingredients you pack in your salad, but spoiler alert: They're all most likely perishable and should be refrigerated ASAP. Lettuce, dairy-based dressings, cheeses, and other produce in your salad, to name a few, should be stored properly at a temperature at 40°F or below. And most protein, such as meat, poultry, eggs, and seafood, should also be refrigerated within two hours of cooking or purchasing, or within one hour if the temperature outside is above 90°F, says Cassell.So basically, unless you're planning on a 10 a.m. lunch, you should store your salad in an insulated lunch bag with an ice pack, or just stick your Tupperware in the office fridge.