In the center of TOK is the knower -a person who knows. I am a knower, you are a knower. But we also belong to various communities of knowers, such as the community of people sharing a particular religious belief, the community of mathematicians, the community of students who learn European history from European textbooks.
The knower has certain knowledge about himself/herself and the world around them. This knowledge can be of two types: 
Personal knowledge is something that belongs to an individual and is not necessarily shared by other individuals.
Shared knowledge is something that is jointly produced by large groups of people. Such knowledge is common to large communities. For example, mathematics is in the domain of shared knowledge.
On the other hand, your intuitions about different types of food and how tasty they are belong to the domain of your personal knowledge. It may or may not be shared by others.
Similarly, physics is shared knowledge, but a student's understanding of physics is that student's personal knowledge.