In our fast-paced lives, microwaves offer unmatched convenience, but not all foods are safe to reheat this way. Processed meats, for example, contain preservatives that can form harmful compounds when microwaved. Beets, rich in nitrates and iron, may oxidize and lose their nutrients during reheating, with some studies linking this to increased cancer risk. Hard-boiled eggs pose a physical hazard; steam buildup can cause them to explode unexpectedly. Potatoes, if improperly stored, can harbor Clostridium botulinum bacteria, which survives reheating and may cause serious foodborne illness.

Other seemingly harmless foods also pose risks. Fruits with high water content, especially when uncut, can burst in the microwave due to internal steam buildup. Hot peppers release capsaicin when heated, potentially irritating your eyes, nose, and throat. Microwaving breast milk is dangerous because uneven heating creates hot spots that can burn a baby’s mouth. Even rice isn’t always safe—Bacillus cereus spores can survive initial cooking and multiply if rice is left out, leading to food poisoning when reheated. Though microwaving saves time, it can reduce nutritional value, compromise flavor and texture, and—more critically—pose health hazards. For certain foods, it’s better to use alternative heating methods or avoid reheating altogether.