You can find out the answers here from Stephanie Nuzzo, from Lifehacker.com.au published the article, click to read. 

This week is Food Safety Week.  The Food Safety Information Council where very straight about their opinion on the ‘sniff test’.

“You can’t tell if a food will give you food poisoning by smelling it. Food can smell or taste fine yet still give you food poisoning.”

In a nutshell, the Food Safety Information Council recommends living by the use-by date. Their views on best before dates are a little more flexible.

The Food Safety website shares that “you must use (or freeze) a food by its ‘use by’ date or it could be a food safety risk”. When working with a best before date, however, the food item “will still be ok to eat after that date but it might have lost some nutrition or quality”.