4. Conclusions
All cheeses made with ewe milk inoculated with clostridia spores showed signs of LBD at different stages of ripening, but the degree of spoilage was species-dependent. C. tyrobutyricum strains resulted potent cheese spoilers, noticeably affecting cheese pH and color and leading to intense blown-packaging, cheese cracking and accumulation of volatile compounds associated with rancid and pungent off-odors at the end of ripening. The metabolism mainly lied on butyric acid fermentation through production of butyric acid and gases, however, other Clostridium metabolic pathways need to be considered, because the high levels of propionic and pentanoic acids and some aldehydes, alcohols and esters associated with cheese off-odors were detected in these cheeses. C. beijerinckii INIA 63 and C. sporogenes INIA 71 gave rise to belated and milder cheese spoilage. However, these cheeses showed a volatile profile different to control cheese and cheeses made with C. tyrobutyricum strains and characterized by higher levels of 2-butanone, 2,3- butanedione and 2-butanol. Finally, the action of C. butyricum CECT 361 on cheese was weak, tardy and insufficient to cause substantial spoilage, notwithstanding a slight blown-pack at the end of ripening, entailing comparable characteristics to control cheese.