Native Microflora in Fresh-Cut Produce Processing Plants and Their Potentials for Biofilm Formation

J Food Prot. 2013 May;76(5):827-32. doi: 10.4315/0362-028X.JFP-12-433.


Representative food contact and nonfood contact surfaces in two mid-sized, fresh-cut processing facilities were sampled for microbiological analyses after routine daily sanitization. Mesophilic and psychrotrophic bacteria on the sampled surfaces were isolated by plating on nonselective bacterial media. Alternatively, bacteria were isolated after an incubation period that allowed the formation of heterogeneous biofilms on stainless steel beads. Of over 1,000 tested isolates, most were capable of forming biofilms, with approximately 30 % being strong or moderate biofilm formers. Selected isolates (117) were subjected to species identification by using the Biolog Gen III microbial identification system. They distributed among 23 genera, which included soil bacteria, plant-related bacteria, coliforms, and opportunistic plant- or human-pathogenic bacteria. The most commonly identified bacteria species were Pseudomonas fluorescens, Rahnella aquatilis, and Ralstonia insidiosa. The high prevalence of R. insidiosa, a strong biofilm former, and P. fluorescens, a moderate biofilm former, suggests that they were established residents in the sampled plants. These results suggest that native microflora capable of forming biofilms are widely distributed in fresh-produce processing environments.

MeSH terms

  • Bacteria / isolation & purification
  • Bacterial Adhesion / physiology*
  • Bacterial Physiological Phenomena*
  • Biofilms / growth & development
  • Colony Count, Microbial
  • Consumer Product Safety
  • Environmental Microbiology*
  • Food Contamination / analysis
  • Food Contamination / prevention & control
  • Food Handling / methods*
  • Food Microbiology
  • Food-Processing Industry*
  • Fruit / microbiology
  • Humans
  • Pseudomonas fluorescens / isolation & purification
  • Pseudomonas fluorescens / physiology
  • Stainless Steel
  • Vegetables / microbiology


  • Stainless Steel