ORCID

0009-0003-3854-5436

Department

Department of Physical Sciences

Year of Study

2

Full-time or Part-time Study

Part-time Study

Level

Postgraduate

Presentation Type

Poster

Supervisor

Dr Michael Callanan

Supervisor

Dr Caitriona Guinane

Abstract

Background

The powdered infant formula (PIF) sector is a growing global market, with Ireland at the forefront of the European exports market; reaching €1.5bn and accounting for 35% of all dairy exports in 2015. However, a major concern associated with PIF is the risk of contamination with the neonatal pathogen Cronobacter sakazakii. Although PIF undergoes thermal treatment during manufacture, it is possible that re-contamination of the product may occur via later processing measures. We investigated the resistance of C. sakazakii to thermal inactivation following inoculation in commercial PIF as a potential treatment for contaminated powder.

Method

Five strains of C. sakazakii cultured in brain heart infusion broth (BHI) were inoculated into dry PIF. Inoculated powder samples were exposed to dry heat at 90℃ for 20 mins and screened for bacterial viability at different time points. Thermotolerant strains were then selected for whole genome analysis.

Results

The C. sakazakii strains tested were significantly reduced by the heat treatment with the exception of one strain, C.sakazakii DPC 6528, which showed only a 1.0 log reduction in cfu/g after exposure to 90℃ for up to 20 mins. Preliminary genomic analysis of DPC 6528 identified a putative genomic island of ~15Kb. Variants of this island have been previously suggested to have a role in thermotolerance.

Conclusion

C. sakazakii DPC 6528 was found to have increased thermotolerance in PIF compared to other strains which may be linked to the presence of a genomic island.

Keywords:

C. sakazakii, Genomic Island, Genome, Powdered infant formula (PIF)

Start Date

2-11-2023 11:15 AM

End Date

2-11-2023 12:00 PM

Included in

Microbiology Commons

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Nov 2nd, 11:15 AM Nov 2nd, 12:00 PM

Investigating the Thermotolerance of Cronobacter sakazakii In Powdered Infant Formula

Background

The powdered infant formula (PIF) sector is a growing global market, with Ireland at the forefront of the European exports market; reaching €1.5bn and accounting for 35% of all dairy exports in 2015. However, a major concern associated with PIF is the risk of contamination with the neonatal pathogen Cronobacter sakazakii. Although PIF undergoes thermal treatment during manufacture, it is possible that re-contamination of the product may occur via later processing measures. We investigated the resistance of C. sakazakii to thermal inactivation following inoculation in commercial PIF as a potential treatment for contaminated powder.

Method

Five strains of C. sakazakii cultured in brain heart infusion broth (BHI) were inoculated into dry PIF. Inoculated powder samples were exposed to dry heat at 90℃ for 20 mins and screened for bacterial viability at different time points. Thermotolerant strains were then selected for whole genome analysis.

Results

The C. sakazakii strains tested were significantly reduced by the heat treatment with the exception of one strain, C.sakazakii DPC 6528, which showed only a 1.0 log reduction in cfu/g after exposure to 90℃ for up to 20 mins. Preliminary genomic analysis of DPC 6528 identified a putative genomic island of ~15Kb. Variants of this island have been previously suggested to have a role in thermotolerance.

Conclusion

C. sakazakii DPC 6528 was found to have increased thermotolerance in PIF compared to other strains which may be linked to the presence of a genomic island.