title: Kinetic model-based prediction of the persistence of Salmonella enterica serovar Typhimurium under tropical agricultural field conditions.
abstract: OBJECTIVE
  Present a kinetic model-based approach for using isothermal data to predict the survival of manure-borne enteric bacteria under dynamic conditions in an agricultural environment.
  
  
  RESULTS
  A model to predict the survival of Salmonella enterica serovar Typhimurium under dynamic temperature conditions in soil in the field was developed. The working hypothesis was that the inactivation phenomena associated with the survival kinetics of an organism in an agricultural matrix under dynamic temperature conditions is for a large part due to the cumulative effect of inactivation at various temperatures within the continuum registered in the matrix in the field. The modelling approach followed included (i) the recording of the temperature profile that the organism experiences in the field matrix, (ii) modelling the survival kinetics under isothermal conditions at a range of temperatures that were registered in the matrix in the field; and (iii) using the isothermal-based kinetic models to develop models for predicting survival under dynamic conditions. The time needed for 7 log CFU g(-1) Salmonella Typhimurium in manure and manure-amended soil to reach the detection limit of the enumeration method (2 log CFU g(-1) ) under tropical conditions in the Central Agro-Ecological Zone of Uganda was predicted to be 61-68 days and corresponded with observed CFU of about 2·2-3·0 log CFU g(-1) , respectively. The Bias and Accuracy factor of the prediction was 0·71-0·84 and 1·2-1·4, respectively.
  
  
  CONCLUSIONS
  Survival of Salm. Typhimurium under dynamic field conditions could be for 71-84% determined by the developed modelling approach, hence substantiating the working hypothesis.
  
  
  CONCLUSIONS
  Survival kinetic models obtained under isothermal conditions can be used to develop models for predicting the persistence of manure-borne enteric bacteria under dynamic field conditions in an agricultural environment.
authors.affiliation: Department of Food Science and Post Harvest Technology, Faculty of Agriculture and Environment, Gulu University, Gulu, Uganda Division of Soil and Water Management, Department of Earth and Environmental Sciences, Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium Department of Food Science and Technology, Makerere University, Kampala, Uganda Division of Mechatronics, Biostatistics and Sensors (MeBioS), Department of Biosystems (BIOSYST), Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Ongeng
authors.forename: C
authors.initials: C
authors.lastname: Muyanja
authors.forename: J
authors.initials: J
authors.lastname: Ryckeboer
authors.forename: D
authors.initials: D
authors.lastname: Springael
authors.forename: A H
authors.initials: AH
authors.lastname: Geeraerd
mesh_terms: D000383:Agriculture; D008372:Manure / Q000382:microbiology; D050296:Microbial Viability; D008954:Models, Biological; D012486:Salmonella typhimurium / Q000254:growth & development*; D012988:Soil Microbiology; D013696:Temperature; D014329:Tropical Climate
chemical_list: D008372:Manure