How do you determine the use by date on foods?

Question: How do you determine the use by date on foods?
- Keywords:
  date,
  food,
  use by
Asked by race44bat to Min, Marcello, Katie, Israel, Dheeraj on 19 Nov 2019.
- Israel Ikoyi answered on 19 Nov 2019:
  
  This date is determined by the manufacturer of the food. They do this by carrying out various tests under various conditions to get the highest quality of the food
- Min Yap answered on 19 Nov 2019:
  
  The use by date on foods are determined by the manufacturer of the food. They do shelf life tests to see how long the foods can be kept before it goes bad, or tastes off.
- Dheeraj Rathore answered on 20 Nov 2019:
  
  Food producers and manufacturers have a few ways – both art and science – to figure out how long their foods will be safe to eat. They do experimentation to determine the shelf life of any food products to set a use by date which tells us that food would go bad or taste weird after this date.
  The best before date on food is about safety. This is the most important date to remember. Foods can be eaten until the best before date but not after. You will see use by dates on food that goes off quickly, such as meat products or ready-to-eat salads.

Question: How do you determine the use by date on foods?