Points 1 and two aren't solved in any way, as the buyer has to trust the producer to not lie when making the entry. In other words, the trust problem here occurs before entry into the database.
Point 4 is already solved with by a multitude of companies selling those temperature-sensible stickers (and adding/removing the stickers is the same vulnerability as adding/removing the iot device).
BTW, with a blockchain solution, these are not at all "impossible to alter". That would only be true for a blockchain that is actually decentralized and heavily mined. That implies a blockchain with a multitude of products using the same chain (e.g. not just an OliveOilChain), but then we approach the scaling border very fast, making a blockchain unusable for this use case.
The blockchain will show in time that X producer sells X amount of extra virgin, virgin, and regular olive oil. This will make it difficult for a small single origin producer claiming that ALL of their output is extra virgin. It would also make it difficult for a small producer to rebrand large volumes of some other olive oil as their own.
As for the temp-sensing stickers - add GPS, encryption and transmitting functions and you can add some cool features to temp sensing stickers.
Finally- there isn't THAT much data involved here for the $$ involved, you could do it on the ethereum blockchain or even the litecoin chain. There are quite a number of ultrasecure blockchains at this point.
An excellent point.
I wonder if a market will emerge from the need to secure (and thus mine) these private blockchains. IE, perhaps Walmart could secure its logistical blockchain by compensating miners in "WalmartCoin", which is redeemable at the store.
Couple of questions though -
How would the IOT device in the shipping load know what temperature the olive oil has been? Please don't say the IOT device can be placed in farms because we are currently talking about a logistics systems.
And even if the IOT was placed in the farms - how would anyone verify if the IOT ie the source of data was hacked. Maybe just enough to show that the farm is producing 10% more extra virgin oil?
How would the blockchain entries be managed? Because remember a block is added via majority rules - PoW or PoS. So, in case of olive oil manufacturing - who would verify if the IOT entry is correct?
What happens if the IOT is not tampered and just malfunctions giving incorrect data?
This is where the human element comes into play, and something the blockchain cannot secure.
However, for the 0.01% of use cases where you can't trust the government (money printing) or where the stakes are too high to rely on the security of a trusted 3rd party, blockchain is great.
These are all timestamped, impossible to alter, and would require an elaborate planned fraud between a number of parties to fake.
How would you do this without blockchain? with a trusted 3rd party. Who can you trust when you are involving the russian govt, chinese govt, and US govt, and EU, and corrupt italian public servants? none of those groups trust any of the other parties completely.