To make sure that no contaminant goes into the market.
To ensure that there is definitive product safety regime in their company to counter any false claim regarding contaminant in the product.
To do whatever is practically possible to eliminate / reduce any contaminant related complaints.
To check fill level, fat content, solid content in the product.
To check product integrity, additional products in the pack, product consistency, product packaging aesthetics, weight variations and so on...
This is just for Food and Beverage industry and then in various industries these machines have number of uses for various applications..