Principal component analysis plot showing the distribution of volatile compounds of 60-day-old cheese manufactured from ewe milk inoculated with spores of Clostridium
tyrobutyricum CECT 4011, Clostridium tyrobutyricum INIA 68, Clostridium butyricum CECT 361, Clostridium beijerinckii INIA 63 and Clostridium sporogenes INIA 71.