Suppose we have a consortium blockchain like Food Trust IBM for supply chain. How can we be sure that the data entered to the blockchain by different parties (who are permissioned to add data) is trusted. I mean, some company may say that its fruits are grown organically, while it is not true. Or some other company might say that it received something at Monday, while the truth is it received it on Sunday. Does the blockchain itself has an algorithm to prevent these kinds of issues, or there must be some other solution like using IoT sensors?
You are right. In order to tackle such problems, there are devices that keep on updating their positions after a specified duration. For example, the GPS sensor on the truck will send its location (and store it on the ledger) after every 15 minutes. So, in this way, that particular problem can be solved.
Similarly, other problems can also be solved.
If you want to learn more about the use of IoT with blockchain (especially Hyperledger Fabric), you can check out this course: https://courses.cognitiveclass.ai/courses/course-v1:IBMDeveloperSkillsNetwork+BC0202EN+v1/course/