Yoghurt is a dairy product, which tend to go bad faster when not refrigerated. If you eat yoghurt that has gone bad, it can lead to digestive issues and diarrhoea, says emergencycareforyou.org.
According to Fit Day, most yoghurt is pasteurised. If this is the case with your yoghurt, it should be fine for several hours without being refrigerated. If your yoghurt is not pasteurised, throw it away after one hour outside of the refrigerator. Also pay close attention to the expiration date, which might mean that your yoghurt will go bad faster out of the refrigerator, says emergencycareforyou.org.
Some yoghurts contain probiotics that aid digestion. According to Nutrition Science News, probiotics die at a faster rate when not refrigerated. Therefore, it's best to avoid yoghurt that has been out of the refrigerator for 30 minutes or more. The yoghurt itself will be OK to eat; however, you will not reap the benefits of the probiotics, making the yoghurt less healthy.
How to Know if Yogurt Has Gone Bad
If you see mould on your yoghurt, do not consume it. If your yoghurt seems overly chunky, this is also a sign that it might be going bad. Sometimes your yoghurt might also smell sour if it has gone bad; however, this is not always the case, so checking for mould is the most sure-fire way to know if it's gone bad.