How can you tell if food has gone bad?

1 Look for signs of spoilage

One of the easiest ways to tell if food has gone bad is to look for visible signs of spoilage, such as mold, discoloration, sliminess, or cracks. These signs indicate that the food has been contaminated by bacteria, fungi, or other microorganisms that can cause foodborne illnesses. You should discard any food that shows signs of spoilage, even if it does not smell or taste bad. Some foods, such as cheese, yogurt, and salami, may have some harmless mold on the surface, but you should cut off the affected parts and consume the rest within a short time.

2 Smell the food

Another way to tell if food has gone bad is to smell it. A foul, sour, or rancid odor is a clear indication that the food is not safe to eat. Some foods, such as meat, fish, eggs, and dairy products, are more prone to developing unpleasant smells when they go bad, due to the breakdown of proteins and fats by bacteria. Other foods, such as fruits, vegetables, and grains, may have a fermented or musty smell when they spoil, due to the production of alcohol and acids by yeasts and molds. You should trust your nose and discard any food that smells off, even if it looks fine.

3 Taste the food

A third way to tell if food has gone bad is to taste it. A bitter, sour, or metallic taste is a sign that the food has undergone chemical or microbial changes that affect its flavor and quality. Some foods, such as nuts, oils, and spices, may taste rancid when they go bad, due to the oxidation of fats and oils by exposure to air and light. Other foods, such as bread, pasta, and rice, may taste stale when they go bad, due to the loss of moisture and freshness. You should taste a small amount of food before eating it, and spit it out and discard it if it tastes bad.

4 Check the labels

When determining whether food has gone bad, you should also check the labels. Most packaged and processed foods have an expected shelf life indicated on the label, but these dates may not always be accurate due to storage conditions, handling practices, and consumer preferences. Therefore, you should use these dates as a guideline rather than a rule and rely on your own judgment and common sense when deciding whether to eat or discard food. Here are some of the terms you may find on food labels and their definitions: 'Sell by' indicates when the retailer should remove the product from the shelf; this date does not necessarily mean that the food is unsafe or spoiled, but it may lose some of its quality and freshness. 'Best by' tells the consumer when to use the product for the best quality and flavor; again, it does not mean that the product is unsafe or spoiled after this date, but it may lose some of its appeal and taste. Finally, 'Use by' is when the consumer should use the product for maximum safety and quality; it does not mean that the product is unsafe or spoiled before this date, but it may become unsafe or spoiled soon after this date.

5 Use common sense

Using common sense is a fifth way to tell if food has gone bad. You should consider the type of food, the storage conditions, the preparation methods, and the consumption habits when deciding whether to eat or discard food. To keep food fresh, store it in a clean, dry, and cool place away from direct sunlight, heat, and moisture. Use airtight containers, bags, or wraps to prevent contamination. Refrigerate or freeze perishable foods as soon as possible and thaw them in the refrigerator or microwave. Keep raw and cooked foods separate and wash your hands, utensils, and surfaces before and after handling food. Follow instructions on packages or recipes for cooking, reheating, and serving food. Cook food to the appropriate temperature and time; use a thermometer to check the doneness. Reheat food until it is steaming hot and do not reheat more than once. Serve food within two hours of cooking or reheating; do not leave it at room temperature for longer than that. Refrigerate or freeze leftovers within two hours of serving; eat or discard them within three to four days. Eat food in moderation and variety; do not overstock or hoard what you may not be able to consume before it goes bad. Plan meals and shopping ahead; buy only what you need and can use within a reasonable time. Rotate your stock; use the oldest products first. Donate or compost any edible food that is past its prime but still edible. Knowing how to tell if food has gone bad can help you enjoy your food more, stay healthy, and reduce waste—so when in doubt, throw it out!

6 Here’s what else to consider

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