I have a sellby date for ground beef, what is the use by?

The USDA suggests cooking or freezing ground beef within 2 days. Beef steaks and roasts, the aforementioned 3 to 5 days. Grinding incorporates surface bacteria and oxygen into the mix decreasing useful shelf life.

Color is neither an indicator of freshness nor doneness (brown meat can be both fresh and undercooked).

Smell can be an indicator of spoilage bacteria but is not an indicator of pathogenic bacteria which (generally) do not smell at all.

All you need to know about ground beef:

http://www.fsis.usda.gov/PDF/Ground_Beef_and_Food_Safety.pdf

Or see chart here:

http://www.fsis.usda.gov/Factsheets/Food_Product_dating/#10

This is from the USDA/FSIS

Use or freeze products with a "Sell-By" date within 3 to 5 days of purchase.

If the manufacturer has determined a "Use-By" date, observe it. This is a quality assurance date after which peak quality begins to lessen but the product may still be used. It's always best to buy a product before its date expires. It's not important if a date expires after freezing beef because all foods stay safe while properly frozen.

Ground beef can spoil pretty quickly. I wouldn't hold it more than two days past the sell by date. And if it's green on the bottom well...

Judge by how the meat looks. If its nice and red, you will probably be fine. If it is starting to go brown, I'd use it sooner than later. You can also freeze it of you don't want to rush using it.