IQF fruit is frozen piece by piece and stays free flowing, so you can pour out exactly the quantity you need. Block frozen fruit is frozen as a solid mass in a carton or bag and must be thawed or broken up before use. IQF costs more per kilogram; block frozen is cheaper and perfectly suited to processing.
Why the two formats exist
Block freezing is older, simpler and uses less energy per kilogram. It suits any application where the fruit is going to be broken down anyway: juice, puree, jam, concentrate. IQF requires a fluidised bed tunnel and careful dewatering upstream, which costs more to run, and it earns that back wherever the fruit has to stay whole and dosable.
Choosing between them
Choose IQF when you portion by weight, dose automatically, or present visible whole fruit. Choose block frozen when the fruit is milled, pressed or cooked, and when your process can absorb a full carton at a time. Mixed sourcing is normal: premium IQF for the visible application, block frozen for the blended one.
The full comparison, including yield and handling, is in IQF vs block frozen berries.