title: Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).
abstract: Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) < Escherichia coli sp. (62 days) < Salmonella sp. (133 days) from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.
authors.affiliation: Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. cmanyi-loh@ufh.ac.za.
authors.forename: Christy E
authors.initials: CE
authors.lastname: Manyi-Loh
authors.affiliation: Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. smamphweli@ufh.ac.za.
authors.forename: Sampson N
authors.initials: SN
authors.lastname: Mamphweli
authors.affiliation: Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. emeyer@ufh.ac.za.
authors.forename: Edson L
authors.initials: EL
authors.lastname: Meyer
authors.affiliation: Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. aokoh@ufh.ac.za.
authors.forename: Anthony I
authors.initials: AI
authors.lastname: Okoh
authors.affiliation: Department of Physics, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. gmakaka@ufh.ac.za.
authors.forename: Golden
authors.initials: G
authors.lastname: Makaka
authors.affiliation: Fort Hare Institute of Technology, University of Fort Hare, Alice Campus, Alice 5700, Eastern Cape Province, South Africa. msimon@ufh.ac.za.
authors.forename: Michael
authors.initials: M
authors.lastname: Simon
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D058491:Bacterial Load; D056804:Biofuels; D019149:Bioreactors; D002167:Campylobacter / Q000302:isolation & purification; D002417:Cattle; D004926:Escherichia coli / Q000302:isolation & purification; D008372:Manure / Q000382:microbiology*; D012475:Salmonella / Q000302:isolation & purification; D018505:Waste Management / Q000379:methods*
chemical_list: D056804:Biofuels; D008372:Manure