That has nothing to do with a blockchain though - the data structure you use has no ties to the physical entities entering data into it. If there's a regulatory

That has nothing to do with a blockchain though - the data structure you use has no ties to the physical entities entering data into it. If there's a regulatory body enforcing compliance, why wouldn't that regulatory body just maintain a database to track the supply chain? More energy efficient, and it aligns the data with its oversight. If there's no regulatory body, then you're back to the original problem - nothing about a blockchain prevents dirty Farm A from entering Farm B into the ledger.