OBJECTIVE (i) To evaluate methods for isolation and molecular detection of blown pack spoilage (BPS) clostridia and (ii) to survey beef abattoirs for sources and distributions of Clostridium estertheticum and Cl. gasigenes. RESULTS Molecular detection and conventional isolation methods were used to detect and recover BPS associated clostridia (Cl. estertheticum and Cl. gasigenes), from four commercial Irish beef abattoirs and their environments, during a one year study. DNA-based methods detected 218 Cl. estertheticum and 300 Cl. gasigenes, from 1680 samples, whereas culture-methods only yielded 17 Cl. estertheticum and 176 Cl. gasigenes isolates. BPS Clostridia were frequently detected in beef abattoirs and their environments, especially at areas prior to hide removal. The study noted a higher percentage of positive samples during the month of May (38.6%). CONCLUSIONS (i) DNA-based techniques are the most reliable ways to determine the presence of these organisms in various samples and (ii) hides and faeces are the main reservoirs of BPS clostridia in the abattoirs. CONCLUSIONS This paper provides useful information to detect BPS organisms, as well as to develop a science-based control strategy of the problem.