INFLUENCE OF RECONSTITUTION TEMPERATURE ON SURVIVAL OF CRONOBACTER SAKAZAKII IN POWDERED INFANT FORMULA

Kelsey C Mcevoy,Carmel M Kealey,Damien B Brady

doi:10.15414/jmbfs.2016.5.5.495-499

Kelsey C Mcevoy, Carmel M Kealey + Show 1 more

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https://doi.org/10.15414/jmbfs.2016.5.5.495-499

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Abstract

Cronobacter spp. are emerging opportunistic pathogens commonly associated with the feeding of powdered infant formula (PIF). This study aimed to investigate the ability of C.sakazakii (ATCC 29544) to survive heat injury in laboratory growth medium and powdered infant formula (PIF) in comparison to Escherichia coli (ATCC 25922) and other selected Cronobacter strains. As part of this work the thin agar layer (TAL) method for the recovery of heat-injured foodborne pathogens was evaluated for use with C.sakazakii (ATCC 29544) and E.coli (ATCC 25922). We report that heat treatment at 55°C for 10 minutes had no significant effect (P > 0.05) on C.sakazakii (ATCC 29544) viability in peptone or PIF. Significant differences in survival of Cronobacter strains after this heat treatment were identified indicating that heat tolerance in this genus may be strain dependent. PIF did not enhance survival of this organism in comparison to other media. Results indicate that a decrease in temperature of 5°C from the recommended 70°C for the reconstitution of PIF was sufficient to produce a significant increase in survival of C.sakazakii (ATCC 29544). Reconstituted PIF stored at room temperature was shown to support the survival and proliferation of this pathogen indicating that temperature abuse during PIF preparation and storage may significantly increase the risk of disease caused by these opportunistic pathogens.

Highlights

powdered infant formula (PIF) is consumed by millions of infants throughout the world every day, and is generally considered as safe (Pagotto & Farber, 2009), it is not a sterile product and can harbour pathogens such as Cronobacter, Salmonella and Staphylococcus (Wang et al, 2012)
This study aimed to investigate the ability of C.sakazakii (ATCC 29544) to survive heat injury in laboratory growth medium and powdered infant formula (PIF) in comparison to Escherichia coli (ATCC 25922) and other selected Cronobacter strains
In 2004, the Food and Agriculture Organisation of the United Nations (FAO) and the World Health Organisation (WHO) jointly convened an expert meeting on Enterobacter sakazakii ( Cronobacter spp.) and other microorganisms in powdered infant formula (PIF) and concluded that intrinsic contamination of PIF with E.sakazakii ( Cronobacter spp.) and Salmonella has been a cause of infection and illnesses in infants

Summary

Introduction

PIF is consumed by millions of infants throughout the world every day, and is generally considered as safe (Pagotto & Farber, 2009), it is not a sterile product and can harbour pathogens such as Cronobacter, Salmonella and Staphylococcus (Wang et al, 2012). The inconsistencies existing in the recommendations for the safe preparation of PIF may prove to be extremely important in terms of preventing infection from intrinsic microorganisms, as even low numbers of organisms in this genus are considered to be a risk factor (FAO & WHO, 2004). This present study compares the efficacy of currently recommended preparation methods in terms of ability to reduce survival of C.sakazakii (ATCC 29544) cells added at the time of preparation. Differences in growth characteristics and tolerance to environmental stresses such as temperature resistance are reported to be strain dependent in some studies (Osaili & Forsythe, 2009; Strydom et al, 2012) and

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