"Use by" and "best buy" dates printed on food products can be invaluable to consumers, in many cases prompting them to discard outdated products they might otherwise ingest. But what if the expiration date has been smudged away and cannot be read? And, more vexingly, what if the "use by" date is still days away but the product looks suspicious? If evaporated milk plays a significant role in your diet, you'll want to know when it turns bad, especially if it's sitting – open but covered – on a shelf in your refrigerator.
Inspect the Milk
Pour the evaporated milk into a bowl so that you can clearly see it. If, like many people, you open evaporated milk by simply puncturing one hole in the top of the can, you will find it impossible to inspect the milk without pouring it out.
Familiarize yourself with how fresh evaporated looks after it has just been opened. It does not look pure white like drinking milk. True to its name, evaporated milk has been heated until more than half of its water content has evaporated. This heating process causes the natural sugars in the milk to caramelize, resulting in a slightly golden color.
Compare the color of fresh evaporated milk to milk that you suspect has gone bad. The latter may be a darker brown.
Check for a film or "milk skin" that may be forming on the evaporated milk. The milk may be curdled or its texture may have thickened noticeably – all signs that the milk is turning bad or has gone bad.
Smell the milk. Bad evaporated milk will smell sour or bitter.
Store Evaporated Milk Properly
Store cans of evaporated milk in a cool, dry place. Throw away cans that are rusted or bulging.
Store open cans of evaporated milk in the refrigerator, but cover them first. Better yet, pour the milk into a sealable bowl so that you can clearly see it and assess its freshness. Use the milk within seven days, just as you would with ordinary drinking milk.
Follow the "use by" or "best by" date imprinted on a can of evaporated milk to enjoy the highest quality. Evaporated milk enjoys a shelf life of about one year, and sometimes longer. Invert the cans once every two months so that the contents don't separate.