Penicillium is aerobic. It can only develop if there are mechanically- made holes in the cheese. For this reason, the grains must be formed - i.e. stirred in vats to avoid the grain matting and continued until each grain has a protective surface film. The whey will be separated from the curd at the time of moulding, thus improving the formation of holes in the cheese.
Following the removal of the whey, moulding is usually carried out with distributors adapted to the shape of the cheeses.
Photo source: CNIEL