That's right, when you are logged in, if you go to the topic you want to move, there is a "post reply" button at the top and at the bottom of the page, the post reply box at the bottom of the page has 3 boxes on the right side of it, the last one is a hammer icon, click that box and a drop down menu list will appear.
Select "move topic" and then it will ask where you want to move it to, select the forum you want to move it to (food chemistry) and then hit submit,
The posts should now be in F1 and F2 will say something like there are no posts in this forum.
Boom.