Pathogenic bacteria in biogas plants using cattle, swine, and poultry manure.

Fugate, a waste product from biogas production, regularly used in agriculture as a fertiliser, may contain bacterial pathogens that cause zoonoses. Anaerobic digestion (AD) can inactivate viable pathogens, including parasites, viruses, and pathogens containing antibiotic resistance genes. This study aimed to compare the numbers of pathogenic bacteria and diversity of potential bacterial pathogens in the fugate using three different types of slurry: cattle, swine, and poultry manure. The swine fugate showed higher numbers of Clostridium perfringens and Campylobacter sp. than the poultry and cattle fugate. In the cattle fugate, the lowest total number of pathogenic bacteria and a low number of coliforms were detected after the AD. The use of cattle manure in biogas plants presents a lower potential for soil contamination with pathogens. The fugate produced using poultry or swine manure can be used carefully to avoid possibility of contamination of aquifers or surface waters. Also fugate produced from manure of cows suffering from chronic botulism can be used only with carefulness because of the presence of Clostridium botulinum spores in biogas waste of diseased cows.