The evolution of sporulating bacteria in full-scale composting facilities with online temperature monitoring has been poorly studied, although organic matter recycling increases. We analysed Clostridium perfringens and sulphite-reducing clostridia (SRC) by cultivation, and streptomycetes by real-time PCR in five full-scale, temperature-monitored and aerated composting processes, and two pilot-scale drum composters. Facilities composted woodchips, sawdust, peat, or bark amended sludge or source-separated biowaste. Streptomycetes genes of 0.21-110 x 10(7) copies/g feed increased fast to 0.019-33 x 10(9) copies/g, and then were equal or decreased. SRC of 0.06-2.2 x 10(7) cfu/g feed decreased to 0-600 cfu/g, with re-growth in two facilities. End products were clean of C. perfringens, detected in sludge composts. Although processes contained large quantities of spore-forming bacteria, in the best facilities end products had the high quality. Temperature (> 55 degrees C, > 2d) was not related to the end compost quality, but relations between waste and bulking agent qualities, aeration, and processing time should be better controlled. (C) 2011 Elsevier Ltd. All rights reserved.