Clean the mushrooms removing the hard and muddy part, wash them quickly in cold water, once drained and dried with a tea towel slice them in segments. Chop the bacon into small cubes and set aside; drain the tuna well from its oil and break it up coarsely. peel the garlic, wash and crush lightly; wash the parsley, dry it delicately with a tea towel and mince it.Heat the oil in a saucepan and shallow fry the garlic and the bacon cubes until golden. Add the mushrooms, brown for a couple of minutes on a high heat, season with a pinch of salt and pepper. Add the bits of tuna and carry on cooking for a couple of minutes; at last add the chopped parsley. Cook the pasta in a saucepan with plenty of boiling salted water, drain it al dente and mix it with the ragù. Serve the fusilli nice and warm.