Selection of Salmonella Typhimurium as an indicator for pathogen regrowth potential in composted biosolids

In order to select a suitable indicator for monitoring the pathogen regrowt h potential of composted biosolids, the growth kinetics of selected bacteri a were investigated. Growth parameters of sis serovars of Salmonella and th ree strains of Escherichia coli in sterilized compost were compared. Seeded Salmonella and E. coli grew rapidly, reaching population densities of more than 10(8) g(-1) after 30 h of incubation. The specific growth rates of Sa lmonella serovars and E, roll strains were similar and varied from 0.49 to 0.55 h(-1). The specific growth rate of the Salm. Typhimurium isolates was significantly higher than the other bacterial strains. It was concluded tha t an antibiotic-resistant strain of Salm. Typhimurium can be used as an ind icator for a pathogen regrowth potential test.