The ability to track food products one step back to the supplier and one step forward to the point of sale.
Under EU Law, you must be able to prove exactly where every ingredient in your kitchen came from. If you decant food into plastic tubs without retaining the batch code and expiry date, you break the traceability chain, and an auditor will force you to discard the product.
No, that is "forward traceability" and is not required for restaurants (unlike manufacturers). You only need "one step back" traceability: knowing exactly which supplier sent you the beef, on what date, and the batch code. This ensures that if a supplier issues a recall for contaminated meat, you can identify if you have that specific batch in your kitchen.
You should keep invoices and delivery dockets for as long as the food is in your possession plus a reasonable period after consumption, but for tax and comprehensive safety reasons, records are typically kept for years. However, for immediate food safety recalls, you must be able to produce the supplier information for any item in your fridge immediately during an inspection.