RANCHO MIRAGE, Calif. -

Americans throw out billions of pounds of food every year, not because the food goes bad, but because of the date on the package.  It's costing millions and affecting landfills. So how do you know if your food is safe to eat? It's all in your nose. 

"I don't trust it," said Desert Hot Springs resident Erasmo Numez.

Use by, sell by, freeze by?  Dates are all over our products.

"I don't want to risk it, it's not worth the risk to my own body," said Numez.

We even found an expiration date on water.  So does the food really go bad when the calendar matches the date printed?  The simple answer is not always. 

"That is just a general rule of when the stores have the responsibility to remove it from the shelf.  It doesn't necessarily mean it is going bad that day," said Clark's Nutrition and Natural Food Market assistant manager Debbie Donnell.

A new study out of Harvard found that 40% of food goes wasted in America.   Part of the reason is people are too quick to throw away food. 

"Maybe a fear of getting sick, maybe not knowing if it maybe good or not if it may be going bad," said Donnell.

Part of the confusion is that there is no universal system for putting dates on products.  Some products say "best by" or "use by" or just list a date. Also the requires for which foods have dates varies state to state. California requires dates be put on Dairy and shellfish, other states require all perishable food, while other have none. 

"There should be a sell by and maybe a eat by, make sure this is consumed by because I really don't know on everything," said shopper Theresa Biggs. 

Donnell says many foods are still good beyond the date printed, the best rule of thumb is to use common sense. 

"If you smell the product, if you taste the product, it still smells and tastes good, it's still usable," said Donnell.

"My husband will taste the milk and say yuck this has got to go and that is when it goes," said Biggs. 

Biggs buys food close to the date printed to save money. Often times stores discount foods that are close to their expiration date.

Eating foods past their expiration date, if they still taste and smell good, is an easy change that could save a family of four over $1,500 a year according to the study.

Also keep in mind we live in the desert, so if you are taking milk home and it's over a 100 degrees, it will spoil faster if it is not kept cool. 

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