Validation of Biomode S.A. Probe4CronobacterTM for the Identification of Cronobacter spp

J AOAC Int. 2019 May 1;102(3):855-864. doi: 10.5740/jaoacint.18-0328. Epub 2018 Nov 20.

Abstract

Background: Probe4Cronobacter test kit is based on the use of a fluorescence-labeled peptide nucleic acid probe (PNA) allied to fluorescence microscopy. A sample is taken after a 24 h enrichment of rehydrated 30 g portions of powdered infant formula (PIF). The method uses ready to use dropper solutions applied directly in the sample. This simple process takes less than 2 h to provide a result. In the presence of Cronobacter species, bright red rod-shaped cells will be visible under a fluorescence microscope. Objective: Probe4Cronobacter validation as a new method for the detection Cronobacter species in Powdered Infant Formula (PIF) under the AOAC Performance Tested MethodsSM (License No. 081702). Methods: The validation study encompassed matrix comparison study, inclusivity and exclusivity testing and robustness studies (stability, kit variation, and ruggedness). Results: The inclusivity and exclusivity testing (50 and 35 strains, respectively) yielded no false negative or false positive results. Probe4Cronobacter was compared to the ISO/TS 22964:2006 in 30 g of PIF samples within method comparison in an unpaired study. A total of 30 samples with both low and high level of inoculation were analyzed by Probe4Cronobacter and compared to the same number of samples screened by ISO/TS 22964:2006. No statistically significant differences between presumptive and confirmed results or between candidate and reference method results were observed. Robustness studies showed a high level of consistency and integrity of the kit when different parameters were varied. The deviation conditions tested did not affect the performance of the kit. Conclusions: Probe4Cronobacter test kit has shown to be a accurate, highly sensitive and robust methods for the detection of Cronobacter spp. in PIF samples.

Publication types

  • Validation Study

MeSH terms

  • Animal Feed / microbiology
  • Animals
  • Cattle
  • Cronobacter / genetics
  • Cronobacter / isolation & purification*
  • Fluorescence
  • Fluorescent Dyes / chemistry
  • Food Microbiology / methods*
  • Glycine max / microbiology
  • Heterocyclic Compounds, 4 or More Rings / chemistry
  • Humans
  • Infant
  • Infant Formula / microbiology
  • Microscopy, Fluorescence / methods
  • Nucleic Acid Hybridization
  • Oryza / microbiology
  • Peptide Nucleic Acids / chemistry*
  • Peptide Nucleic Acids / genetics
  • RNA, Bacterial / genetics
  • Water Microbiology

Substances

  • Fluorescent Dyes
  • Heterocyclic Compounds, 4 or More Rings
  • Peptide Nucleic Acids
  • RNA, Bacterial
  • alexa 568