A sour smell, discoloration and the growth of mold are all signs that orange juice has gone bad and should be discarded. The sour smell is typically the first noticeable sign of spoilage, while mold growth is one of the last.
When any abnormal odor or mold appears in orange juice, the juice should be thrown away without tasting. The sour smell that occurs in orange juice is caused by micro-organisms entering the juice and beginning to ferment it. In some cases, this may smell similar to wine, beer, vinegar or other alcohols. When microorganisms are present, the container holding the juice may also swell or even burst if the fermentation process is allowed to continue unchecked.
An unopened container of orange juice lasts for one to two weeks in the refrigerator, while an opened container of orange juice lasts for five to seven days. Once the juice is opened, it should be stored in a container with a tight-fitting lid to prevent contaminants and moisture from entering, which can shorten the shelf life further. After opening, orange juice should be stored promptly in the refrigerator to prevent the growth of bacteria. Orange juice can also be frozen to extend its shelf life further.