[noddy1]

"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."

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.