Your nose is one of the best tools you can use to access your food’s freshness. If the food smells sour or just off, don’t take any chances and just throw it away. Other pointers to look out for are a change of color, as it is the case with guacamole that tends to turn brown and will no longer be enjoyable to eat. Vegetables, fruit, and greens, may also start browning on the edges, whereas meat and seafood can become slimy and sticky to the touch when it goes bad.
Mold of any kind is also a surefire sign that it’s time to toss the food in the trashcan. Lastly, if you happen to reheat the food and take a bite only to realize the taste is stale, rancid, or sour, avoid eating it as well.
To prevent food from spoiling and extend their shelf life, follow these useful tips:
1. Refrigerate leftovers within 1-2 hours maximum. Keeping foods at room temperature for a long time is a very bad idea, as bacteria and other pathogens thrive at temperatures between 40°F (4°C) and 140°F (60°C). If you're outdoors and the temperature is above 90°F (32°C), you need to put things in the fridge even quicker - no more than 1 hour.
2. Store in shallow containers. Food in shallow containers will cool off quicker and more evenly than in tall ones, so opt for shallow ones. US food storage guidelines also recommend avoiding stacking more than 2 containers on top of one another because this may slow down the registration speed of the middle containers. Lastly, opt for sealable clear containers, jars, or bag, so that you can see which foods you have in the fridge clearly.
Sealing is important to extend freshness and prevent germs from getting in or out of the container. Note that this also means you'll have to transfer improperly packaged foods you got from a takeaway menu or brought from a restaurant.
3. Take advantage of the freezer. Refrigerating foods isn't the best method of preserving food for a long time, as the temperature in the fridge isn't low enough. To extend the shelf life of ready-made foods, soup, bread, and cooked meat included, you can put them in the freezer. Most leftover foods will be safe to eat even after 3 months of being in the freezer! One thing to consider when freezing foods, however, is properly sealed packaging (see the point above) to prevent freezer burn.
4. Whenever possible, store different foods separately. For example, keep rice, a side dish, in a separate container from stewed vegetables or seafood. This way, if one of the foods goes bad, you’ll be still able to utilize the rest.
5. When reheating food, bring them to more than 165°F (74°C) to kill any germs that may have survived in the refrigeration. It is known that some foodborne pathogens, such as Listeria monocytogene can survive cold temperatures. If possible, you can even bring some foods to a boil, especially liquids, e.g. soups, sauces, and gravies, before eating.