Survival of salmonellas and Ascaris suum eggs in a thermophilic biogas plant.

In a continuous biogas plant, receiving manure from 200 dairy cows and 400 calves and young stock, survival of salmonellas and Ascaris suum eggs was studied. The bacteria and parasite eggs were kept in filter sacs in the manure that had a temperature of 55 degrees C. No viable salmonellas or Ascaris suum eggs could be found after 24h in the digester. Survival of salmonellas and Ascaris suum eggs was also studied in the manure pit where the manure was stored after digestion. The temperature in the manure pit varied between 22-27 degrees C. Salmonellas survived 35 but not 42 days. On day 56, when the experiments had to be stopped, 60% of the Ascaris eggs were viable.