Rapid detection of Cronobacter spp. in powdered infant formula by thermophilic helicase-dependent isothermal amplification combined with silica-coated magnetic particles separation.

Cronobacter spp. (previously Enterobacter sakazakii), an opportunistic food-borne pathogen, involved in fatal infections in neonates and infants. Contaminated powdered infant formula (PIF) was considered to be the uppermost infective resource. In the present study, a thermophilic helicase-dependent isothermal amplification (tHDA) based method combined with silica-coated magnetic nanoparticles (Si-MNPs) as a DNA separator for rapid and sensitive detection of Cronobacter has been developed. The whole detection process can be completed in <3 h, with a detection limit of 10 and 10 CFU/ml Cronobacter in pure culture and artificially contaminated PIF, respectively, with a great sensitivity (94%) and specificity (100%). Hence, this protocol might be useful for screening and monitoring the contamination of Cronobacter spp. in food industry, and helpful for avoiding the economic loss by retard of feedback of the contamination of pathogens in dairy products.