A laboratory study of survival of selected microorganisms after heat treatment of biowaste used in biogas plants.
The aim of the study was to assess the effect of pasteurisation, as set by the European regulation EC 1774/2002, on selected pathogens and indicator organisms. Unpasteurised substrate (biowaste), including animal by-products from a full-scale biogas plant was heat treated under laboratory conditions at 70 degrees C and 55 degrees C for 30 min and 60 min. Heat treatment at 55 degrees C for 60 min was not sufficient to achieve a hygienically acceptable product. Heat treatment at 70 degrees C for 30 min and 60 min was effective in reducing pathogenic bacteria, Ascaris suum eggs, Swine vesicular disease virus and indicator organisms. However, this level of pasteurisation will still not reduce the quantity of Clostridia spores, or completely inactivate heat-resistant viruses such as Porcine parvovirus or Salmonella phage 28B. The results still give cause for some concern regarding the use of digested residue from biogasplants in agriculture.
National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden. Leena.Sahlstrom@sva.se
Leena
L
Sahlström
Elisabeth
E
Bagge
Eva
E
Emmoth
Annika
A
Holmqvist
Marie-Louise
ML
Danielsson-Tham
Ann
A
Albihn
D036002:ADP Ribose Transferases / Q000302:isolation & purification; D000693:Anaerobiosis; D000818:Animals; D017165:Ascaris suum / Q000502:physiology*; D001419:Bacteria / Q000302:isolation & purification / Q000472:pathogenicity*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D003013:Clostridium / Q000145:classification / Q000302:isolation & purification / Q000472:pathogenicity; D015169:Colony Count, Microbial; D029822:Enterovirus B, Human / Q000472:pathogenicity; D019453:Escherichia coli O157 / Q000302:isolation & purification / Q000472:pathogenicity; D005243:Feces / Q000382:microbiology / Q000469:parasitology / Q000821:virology; D017408:Guidelines as Topic / Q000592:standards; D006358:Hot Temperature; D006801:Humans; D008089:Listeria monocytogenes / Q000302:isolation & purification / Q000472:pathogenicity; D010063:Ovum / Q000502:physiology; D010271:Parasites / Q000302:isolation & purification / Q000472:pathogenicity*; D028323:Parvovirus, Porcine / Q000472:pathogenicity; D012037:Refuse Disposal / Q000379:methods*; D013534:Survival; D013552:Swine; D013997:Time Factors; D037521:Virulence Factors / Q000302:isolation & purification; D014780:Viruses / Q000302:isolation & purification / Q000472:pathogenicity*
D037521:Virulence Factors; D036002:ADP Ribose Transferases; C415223:spvB protein, Salmonella enterica virulence plasmid