Update on Enterobacter sakazakii contamination of powdered infant formulas



    In response to the urgent situation of contamination of powdered infant formulas by the highly virulent Enterobacter sakazakii (see INFACT Canada Newsletter Spring 2002, How safe are infant formulas?), Health Canada has issued a Health Professional Advisory.


    Notable in the recommendations there was no mention of breastfeeding or the provision of banked human milk as the safest means to feed infants who have special needs or who may be immunocompromised.



Highlights from the advisory


Enterobacter sakazakii infection and powdered infant formula – background


    On April 9, 2002, the United States Food and Drug Administration (USFDA) issued an alert to U.S. Health Care Professionals regarding the risk associated with Enterobacter sakazakii infections among neonates fed milk-based,  powdered infant formulas. Historically, there have been several small E. sakazakii outbreaks reported among infants fed milk-based, powdered formula products from various manufacturers. In addition to powdered milkbased formulas, powdered human milk fortifiers may also pose a hazard.


    E. sakazakii is a rare, but lifethreatening cause of neonatal meningitis, sepsis, and necrotizing enterocolitis. In general, the reported case-fatality rate varies from 40-80% among newborns diagnosed with this type of severe infection. The type of meningitis caused by E. sakazakii may lead to cerebral abscess or infarction with cyst formation and severe neurologic impairment.


    Reports have also suggested a correlation between E. sakazakii infection and powdered infant formulas. Similarly, it has been reported that premature infants and those with underlying medical conditions may be at highest risk for developing an E. sakazakii infection.


     Several outbreaks of E. sakazakii, in Neonatal Intensive Care Units (NICUs), have been reported worldwide including countries such as England, Netherlands, Greece, U.S. and Canada. In Canada, two incidents of neonatal meningitis caused by E. sakazakii were reported in two Canadian hospitals (1990, 1991). It should be noted that healthy infants may not always be immune to E. sakazakii infections.


     Health Canada is drawing attention to the fact that powdered infant formulas are not commercially sterile products. Unlike liquid formulas, which are subjected to sufficient heat to render them commercially sterile, powdered infant formulas are not processed at high enough temperatures for sufficient time to achieve commercial sterility. Human milk fortifiers which are added to preterm breast milk are also available in powdered or liquid forms. A number of formulas, including formulas for infants with metabolic conditions, are available only in powdered form. Powdered soy-based infant formulas may also become contaminated with E. sakazakii through improper cleaning of production lines and may, therefore, pose a safety hazard.




     Based on the above, Health Canada recommends that formula products be selected based on nutritional and medical needs. Whenever possible, an alternative to powdered formulas, such as ready-to-feed and concentrated

liquid formulas, should be chosen in the NICU setting and for immunocompromised infants. If there is no alternative, the following steps will help control or minimize the risk:


    Preparation of powdered infant formulas in a laminar flow hood by trained personnel and using sterilized water, which should minimize contamination from the environment. Refer to the following document for detailed procedures. Preparation of Formula for Infants: Guidelines for Health-Care Facilities,  American Dietetic Association (updated April, 2002). Website: www.eatright.org/formulaguide.html (official document in English; a French translation is available on Health Canada’s Website.)


    Health Canada urges Health Care professionals to promptly report adverse symptoms associated with the consumption of infant formulas to the nearest Canadian Food Inspection Agency (CFIA).


    At present, Health Canada is determining whether additional precautionary steps are required to ensure the safe manufacturing and handling of infant formulas.



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