title: Possible influence of surfactants and proteins on the efficiency of contact agar microbiological surface sampling.
abstract: Agar contact microbiological sampling techniques, based on a transfer of the microorganisms present on a surface to a culture medium, are widely used to assess and control surface cleanliness and to evaluate microbial contamination levels. The effectiveness of these techniques depends on many environmental parameters that influence the strength of attachment of the bacteria to the surface. In the present study, stainless steel and high density polyethylene surfaces were inoculated with known concentrations of Staphylococcus epidermidis. Following an experimental design, the surfaces were sampled with different types of replicate organism direct agar contact plates and Petrifilm; results indicated that recovery rates were influenced by the presence of egg white albumin or Tween 80 in the inoculum solutions or by the introduction of surfactants into the contact agar of the microbiological sampling techniques. The techniques yielded significantly different results, depending on sampling conditions, underlining the need for a standardization of laboratory experiments to allow relevant comparisons of such techniques.
authors.affiliation: Department of Food Technology, Computer Science and Mathematics, Liege University, Gembloux Agro-Bio Tech, BE-5030 Gembloux, Belgium.
authors.forename: Sylvie M
authors.initials: SM
authors.lastname: Deckers
authors.forename: Marianne
authors.initials: M
authors.lastname: Sindic
authors.forename: Christine
authors.initials: C
authors.lastname: Anceau
authors.forename: Yves
authors.initials: Y
authors.lastname: Brostaux
authors.forename: Jean G
authors.initials: JG
authors.lastname: Detry
mesh_terms: D000362:Agar; D001431:Bacteriological Techniques; D015169:Colony Count, Microbial / Q000379:methods*; D004783:Environmental Microbiology; D004784:Environmental Monitoring / Q000379:methods*; D004866:Equipment Contamination; D020959:Polyethylene; D013193:Stainless Steel; D013212:Staphylococcus epidermidis / Q000254:growth & development*; D013501:Surface-Active Agents / Q000494:pharmacology
chemical_list: D013501:Surface-Active Agents; D013193:Stainless Steel; D000362:Agar; D020959:Polyethylene