You have many vendors that handle the product. The farm, multiple distributors, and transportation companies.
Having a consolidated/consistent view of transactions from the full supply chain relative to tangible product could be genuinely helpful for reducing errors that could be consequential from a food safety perspective. It's unlikely to stop cheating since many of these food vendors will almost certain being humans entering transactions at keyboards (and then when you can get compliance with that transaction entry) and at those points all you can do is make cheating harder.
The challenge is how to get that consolidated/consistent view of the world across disparate parties, some of which don't know all of the other parties involved, in a secure enough manner, and in a way that the supply chain participants will be willing to take part in.
Larger players, like Walmart, can set the stage for some of that cooperation to happen just because of their relevance to the market. The government agencies that buy food also want that and also are pushing for it (that's where my clients are getting some pushes in that direction). None of that means the end goal will be achieved for any number of reasons, including many that are not technical in nature... "blockchain" just complicates those odds.
