Centralized infant formula preparation room in the neonatal intensive care unit reduces incidence of microbial contamination

Increasing concern regarding potential pathogens in infant formulas led to this evaluation of the influence of procedural and environmental factors on infant formula contamination. In two phases of study, a total of 526 formula samples were analyzed for contamination. In Phase 1, conducted from October 2001 through May 2002, nursing staff prepared formulas in the neonatal intensive care unit at bedside; in Phase 2, conducted from February 2006 through June 2006, dietetic technicians prepared formulas in a centralized feeding preparation room. Two types of formula, ready-to-feed and powder, were sampled. Each sample was divided into two portions; the first was cultured immediately, and the second after 8 hours at room temperature. Multivariate binary logistic regression models were tested to identify the major factors contributing to contamination. Results showed formulas prepared at bedside were 24 times more likely to show contamination than those prepared in a central location (P<0.001) and that powdered formulas were 14 times more likely to be contaminated than ready-to-feed formulas (P<0.001). In addition, samples that had been warmed (P<0.050) and those that were either milk-based or casein hydrolysate (P<0.001) were more likely to be contaminated. This study suggests that centralized feeding preparation results in a significant decrease in prevalence of microbial growth. Because contamination risk increases significantly with the use of powdered formulas, sterile liquid formulas should be considered when possible to minimize risk of microbial exposure in the neonatal intensive care unit population.