Organic Waste Recycling

Composting 133

Table 3.6 Thermal death points of some common pathogens and parasites

Organisms Thermal death point

Salmonella typhosa No growth beyond 46°C; death within 30 minutes at

55 °C to 60°C

Salmonella spp. Death within 1 hour at 55°C; death within 15 minutes

to 20 minutes at 60°C

Shigella spp. Death within one hour at 55 °C

Escherichia coli. Most die within one hour at 55°C, and within 15 to 20

minutes at 60°C

Entamoeba histolytica cysts Thermal death point is 68°C

Taenia saginata Death within 5 minutes at 71°C

Trichinella spiralis larvae Infectivity reduced as a result of one hour exposure at

50 °C; thermal death point is 62-72°C

Necater americanus Death within 50 minutes at 45°C

Brucella abortus or suis Death within 3 minutes at 61°C

Micrococcus pyogenes var.

aureus

Death within 10 minutes at 50°C

Streptococcus pyogenes Death within 10 minutes at 54°C

Mycobacterium tuberculosis

var.hominis

Death within 15 to 20 mins at 66°C, or momentary

heating at 67°C

Corynebacterium diptheriae Death within 45 minutes at 55°C

Table 3.7 Epidemiological effects to compost workers (Clark et al. 1984)

Excess of nasal, ear and skin infections (by physical exams) in compost and

intermediate-exposed workers

Symptoms of burning eyes and skin irritation higher in compost and intermediate-

exposed workers

Fungal colonies greater in cultures from compost workers

Legionella infections not associated with compost exposure but were higher among all

workers exposure categories in Philadelphia-Camden area than in Washington, D.C.,

area

Evidence of higher white blood cell counts and hemolytic complement in compost

workers

Higher antibody levels to compost-endotoxin in compost workers