Muslins smell of sick

I’m sorry this is gross 🤮 but our muslins stink of gone off milk (baby’s sick) even after I was them!! I wash baby’s things in 60 degrees, put washing liquid and detergent in with wash and they still smell afterwards. I don’t know what to do, the smell is really getting to me and it’s not pleasant. It’s literally only the muslins, clothes and everything else are absolutely fine and smell amazing after washes so I don’t get why the smell doesn’t come out of the muslins?? Anyone has the same or got any advice?