definition
Last update: 22/05/2026
Cronobacter species are a genus of Gram-negative, facultatively anaerobic, non-spore-forming, motile, rod-shaped bacteria within the family Enterobacteriaceae [1]. Originally classified as yellow-pigmented Enterobacter cloacae and later Enterobacter sakazakii, the genus was formally redefined in 2008 and currently comprises seven distinct species: C. sakazakii, C. malonaticus, C. turicensis, C. muytjensii, C. dublinensis, C. universalis, and C. condimenti [2], [3]
From a risk-based regulatory perspective, Cronobacter is recognized by Codex Alimentarius, the European Food Safety Authority (EFSA), and the U.S. Food and Drug Administration (FDA) as a severe opportunistic pathogen [4]. While it can cause illness in all age groups, it is primarily associated with life-threatening neonatal infections, including sepsis, meningitis, and necrotizing enterocolitis (NEC), often with high fatality rates (40–80%) [3], [1]. Its defining food safety characteristic is its exceptional desiccation tolerance, allowing it to persist for years in low-moisture foods and production environments, particularly Powdered Infant Formula (PIF).
Cronobacter spp. are particularly resilient, with the ability to form biofilms and a high resistance to osmotic stress and desiccation, primarily due to their capsule production. These traits enhance their persistence, especially in dry environments such as powdered milk processing plants. The bacterium can survive for up to two years in dry conditions, with water activity (aw) levels ranging from 0.14 to 0.27 in dry products. Their generation time varies with temperature: 300 minutes at 10°C, 40 minutes at 23°C, and 20 minutes at 37°C. Additionally, they can utilize sialic acid as their sole carbon source, which facilitates growth in breast milk and infant formula. [1]
