Basically there are three routes by which Enterobacter sakazakii can enter infant formula:
a) through the raw material used for producing the formula;
b) through contamination of the formula or other dry ingredients after pasteurization; and
c) through contamination of the formula as it is being reconstituted by the caregiver just prior to feeding.
Enterobacter sakazakii has been detected in other types of food, but only powdered infant formula has been linked to outbreaks of disease.