Perspective on the risk to infants in the Netherlands associated with Cronobacter spp. occurring in powdered infant formula

Cronobacter spp. has been responsible for severe infections in infants. Relative risks associated with this organism in powdered infant formula (PIF) have been described in several studies. To set priorities and decide on risk management options, it is important for risk managers to have a quantitative perspective on the absolute level of risk of this pathogen within the totality of the burden of illnesses in the population. This study set-out to establish such a perspective for The Netherlands. It addresses the impact of heterogeneity in the distribution of the micro-organism in PIF on risk levels. Based on the assumptions in this study, 60% of formula-fed infants are estimated not to be exposed to Cronobacter spp. during their neonatal period. The mean exposure was calculated to be about 1 cfu per infant over the total neonatal period. Even after thorough mixing, artificially contaminated powder shows counts which are more variable than expected from a normal, homogeneous distribution. Therefore, mean exposure levels may not represent a good basis for calculating risks. The burden of disease of Cronobacter infections to the Dutch population was estimated to be 19–24 Disability Adjusted Life Years (DALYs) per year, of which 95% are due to meningitis. As compared to other illnesses Cronobacter infections represent 0.5–2.4% of the total estimated burden of foodborne infections and intoxications. The organism is estimated to be responsible for 0.5–0.7% of the meningitis burden to the entire population of The Netherlands.