Leftovers are surely one of our main love-hate relationships in life – we hate their taste, but we love the fact that they’re quickly prepared. If you’re someone who enjoys any kind of leftover without thinking whether the food is safe to be reheated, this article is going to shock you!

We usually microwave our leftovers from the previous day, but have you ever wondered if it’s safe to do so? According to the Food Standards Agency, the secret of eating safely lies in the four C’s – cooking, cleaning, chilling and cross-contamination.

Cooking meat is important for eliminating certain bacteria, but reheating food should not be done more than once.

Here are some foods that should never be re-heated:


The problem with reheating rice lies in the way it’s being stored. The Food Standards Agency says that improperly cooked rice may contain spores of bacteria that can survive the cooking process and will multiply if the leftover rice is not kept at the right temperature. The bacteria can cause diarrhea and vomiting once they enter the body.

Reheating the leftover rice won’t help as the spores can survive high temperatures. This is why it’s recommended to eat all the rice once it’s prepared and put any leftovers in the fridge. Don’t let rice sit at room temperature for more than an hour – the more you keep it outside of the freezer, the more the dangerous spores are spreading.

Vegetable oils

Reheating meals made with vegetable oils will do you no good. This increases the risk of heart attack, strokes and even cancer! According to a recent research, reheating polyunsaturated oils that contain linoleic acid (canola, corn, soybean, sunflower oil) releases a toxic compound which causes numerous health problems. The compound is a fatty acid-derived toxin called 4-hydroxy-trans-2-nonenal (HNE). Several studies have confirmed that HNE causes cardiovascular diseases, stroke, Parkinson’s, Alzheimer’s and Huntington’s disease, as well as liver disease and cancer. Here’s what Jeannie Moloo, the spokeswoman for the American Dietetic Association, said about reheating vegetable oils: “If a person is concerned about the health aspects of HNE, then my recommendations would be to never heat any oil to the point of smoking and, as far as cooking at home goes, just use the oil one time.”


Some people claim that reheating leafy green veggies makes them poisonous, but it’s actually the way you store vegetable leftovers that’s making them dangerous. The Center for Food Safety recommends storing leftover veggies in temperatures below 4 degrees or lower, and if you’re planning on storing them for more than 12 hours, you should freeze them.

Most vegetables such as spinach, lettuce, celery or beets are rich in nitrate, a compound that can transform to dangerous nitrites when left on room temperature. Nitrate consumption has been linked with a blood disorder called methemoglobinemia in infants and children, which causes symptoms such as headaches, fatigue, shortness of breath and seizures.