Scientific journal

55 2016

Journal of Food and Nutrition Research
Summary No. 3 / 2016

Kaclíková, E. – Oravcová, K.
Identification of thermotolerant Cronobacter strains using multiplex real-time polymerase chain reaction
Journal of Food and Nutrition Research, 55, 2016, No. 3, s. 278-281

Eva Kaclíková, Department of Microbiology, Molecular Biology and Biotechnology, Food Research Institute, National Agricultural and Food Centre, Priemyselná 4, 824 75 Bratislava 26, Slovakia. E-mail:

Received 5 April 2016; 1st revised 12 May 2016; accepted 13 May 2016; published online 26 May 2016.

Summary: Cronobacter sp. is considered an opportunistic pathogen implicated in food-borne life-threatening infection, in particular in neonates and infants. Contaminated powdered infant formula was identified as the primary source of Cronobacter sp. at very low levels. Multiplication of survived cells of thermotolerant Cronobacter strains was often found a crucial factor for causing outbreaks. The aim of our work was to develop and evaluate a detection method for thermotolerant Cronobacter strains using triplex TaqMan real-time polymerase chain reaction (PCR) targeting a specific sequence for Cronobacter sp., a thermotolerance marker and an internal amplification control. The proposed method was evaluated on 48 strains, including 32 Cronobacter sp. and 16 related species of Enterobacteriaceae family. The results showed 100% inclusivity and exclusivity, and 100% correlation with the time required to kill 90% of cells exposed at 58 °C (D58-value). The developed real-time PCR method facilitated rapid and specific detection of thermotolerant Cronobacter strains isolated from powdered infant formula products or from the production chain.

Keywords: Cronobacter; thermotolerance; multiplex real-time polymerase chain reaction; powdered infant formula

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