There are three main things you need to check.
Chicken is the number one food that causes food poisoning. So it makes sense that people want to know how to tell if chicken is bad. Here's advice from the United States Department of Agriculture Food Safety and Inspection Service (USDA) and a dietitian on how to tell if chicken has gone bad.
How to tell if raw chicken is bad
Check the date
Checking the date is the first step to see if raw chicken is safe to eat. If the printed date passed, the quality of the meat isn't that great, although it's still usable. The USDA recommends people cook raw chicken within one or two days of the date on the package. The advice differs per type of meat, however, so note how long these meats last in the fridge.
Use your senses
Check with your eyes, nose, and fingers before eating chicken that might be bad. Raw, fresh chicken that isn't bad does have a very faint, mild odor, according to Malina Malkani, MS, RDN, CDN, the Media Spokesperson for the Academy of Nutrition and Dietetics. Spoiled chicken, however, has an obvious rancid or sour smell. And as it spoils, the color of the chicken changes from pinkish to grayish, Malkani says. And rather than having a moist, glossy feel, rotten chicken is covered in a thick layer of what seems like sticky slime, adds Malkani, creator of the Wholitarian Lifestyle. If you're still in the store buying chicken, the package should feel cold to the touch, per the USDA.
How to tell if cooked chicken is bad
Cooked chicken lasts three to four days in the refrigerator, according to Malkani. If you're unsure, use your senses again to check if cooked chicken is inedible. "Other signs that chicken has gone bad are foul odors, a slimy texture, and a change in color from white or brown to grayish, greenish, or moldy," Malkani says. Meat that changes color is one of the things that food poisoning experts never eat.
Remember, how to tell if chicken is bad comes down to color, texture, and odor. If one or more of these things seem "off," it's a safe bet to toss it out. If your chicken passes all these tests, however, make sure you also know how to cook chicken breast the right way.
Here's How to Tell If Chicken Has Gone Bad, Source:https://www.rd.com/food/how-to-tell-if-chicken-is-bad/