Cronobacter spp. (formerly Enterobacter sakazakii) are microorganisms present in the environment and can survive in dry foods, such as powdered infant formula.  Cronobacter spp. infections among infants younger than 12 months have high case-fatality rates.  Historical surveys of powdered infant formula have reported a relatively high prevalence rate, ranging from 2 to 15% of Cronobacter spp. contamination in these products.  FDA regulations specify that manufacturers of infant formula must establish a system of production and in-process controls, covering all stages of processing, that is designed to ensure that infant formula does not become adulterated due to the presence of Cronobacter spp (see 21 CFR parts 106 and 107).  In late 2021 and early 2022, a series of Cronobacter spp. illnesses among infants in the U.S. was associated with feeding powdered infant formula.  In each illness, the formula was produced by a specific manufacturer at one facility. The resulting voluntary recall (and the temporary shutdown of the plant) was a major contributing factor to the infant formula shortage experienced across the U.S. in 2022.  Better understanding of the factors that contribute to Cronobacter spp. contamination of powdered infant formula and the production environment is needed to increase the effectiveness of prevention and management strategies.

Cronobacter spp. (formerly Enterobacter sakazakii) are microorganisms present in the environment and can survive in dry foods, such as powdered infant formula.  Cronobacter spp. infections among infants younger than 12 months have high case-fatality rates. Historical surveys of powdered infant formula have reported a relatively high prevalence rate, ranging from 2 to 15% of Cronobacter spp. contamination in these products. FDA regulations specify that manufacturers of infant formula must establish a system of production and in-process controls, covering all stages of processing, that is designed to ensure that infant formula does not become adulterated due to the presence of Cronobacter spp (see 21 CFR parts 106 and 107). In late 2021 and early 2022, a series of Cronobacter spp. illnesses among infants in the U.S. was associated with feeding powdered infant formula. In each illness, the formula was produced by a specific manufacturer at one facility. The resulting voluntary recall (and the temporary shutdown of the plant) was a major contributing factor to the infant formula shortage experienced across the U.S. in 2022. Better understanding of the factors that contribute to Cronobacter spp. contamination of powdered infant formula and the production environment is needed to increase the effectiveness of prevention and management strategies.

1. What is the current prevalence and level of Cronobacter spp. contamination in powdered infant formula in the U.S. market? What is known about Cronobacter spp. in other foods and in the home environment and the frequency with which these foods and environmental sources contribute to human infections?
2. What factors (e.g., virulence factors, host factors, dose of exposure) place an infant at greater risk for Cronobacter spp. infection and serious adverse health consequences or death?
3. What food safety management practices (e.g., facility and equipment design, hygienic zoning and packaging, preventive controls, verification activities) should manufacturers of powdered infant formula employ to further reduce the risk of Cronobacter spp. contamination of formula and/or the production environment?  
4. Given that powdered infant formula is not sterile, how could food safety messaging be improved for infant care providers, with emphasis on use of sterile, ready-to-use formulas for infants at greatest risk and safe infant formula preparation and storage for infant formula in general?