title: Tetrazolium reduction allows assessment of biofilm formation by Campylobacter jejuni in a food matrix model.
abstract: OBJECTIVE
  To develop a staining method for specific detection of metabolically active (viable) cells in biofilms of the foodborne pathogen Campylobacter jejuni.
  
  
  RESULTS
  Conversion of 2,3,5 triphenyltetrazolium chloride (TTC) to insoluble, red 1,3,5-triphenylformazan (TPF) was dependent on metabolic activity of Camp. jejuni. When used with chicken juice, TTC staining allowed quantification of Camp. jejuni biofilm levels, whereas the commonly used dye, crystal violet, gave high levels of nonspecific staining of food matrix components (chicken juice). The assay was optimized to allow for monitoring of biofilm levels and adapted to monitor levels of Camp. jejuni in broth media.
  
  
  CONCLUSIONS
  Staining with TTC allows for the quantification of metabolically active Camp. jejuni and thus allows for quantification of viable cells in biofilms and food matrices. The TTC staining method can be adapted to quantify bacterial cell concentration in a food matrix model, where the accepted method of A600 measurement is not suitable due to interference by components of the food matrix.
  
  
  CONCLUSIONS
  2,3,5 Triphenyltetrazolium chloride (TTC) staining is a low-cost technique suitable for use in biofilm analysis, allowing rapid and simple imaging of metabolically active cells and increasing the methods available for biofilm assessment and quantification.
authors.affiliation: Institute of Food Research, Gut Health and Food Safety Programme, Norwich, UK.
authors.forename: H L
authors.initials: HL
authors.lastname: Brown
authors.forename: A H M
authors.initials: AH
authors.lastname: van Vliet
authors.forename: R P
authors.initials: RP
authors.lastname: Betts
authors.forename: M
authors.initials: M
authors.lastname: Reuter
mesh_terms: D000818:Animals; D018441:Biofilms; D016123:Campylobacter jejuni / Q000254:growth & development / Q000378:metabolism*; D002645:Chickens / Q000382:microbiology; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology / Q000379:methods*; D005562:Formazans / Q000378:metabolism; D005840:Gentian Violet; D008460:Meat / Q000382:microbiology; D050296:Microbial Viability; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods*; D013778:Tetrazolium Salts / Q000378:metabolism*
chemical_list: C510333:1,3,5-triphenylformazan; D005562:Formazans; D013778:Tetrazolium Salts; C009591:triphenyltetrazolium; D005840:Gentian Violet
keywords: 2,3,5 triphenyltetrazolium chloride; Campylobacter jejuni; biofilm; crystal violet; food matrix