Use of commercial human milk fortifiers, however, is not without complications as demonstrated by the observation of a marked increase in metabolic acidosis associated with the introduction of a new fortifier.Human milk fortifiers have also been associated with increased markers of oxidative stress compared to unfortified human milk and to infant formula.In addition, bacterial contamination of powdered infant formulas and associated sepsis has been well documented, resulting in more than 100 cases of neonatal Cronobacter (Enterobacter sakazakii) infections leading to high mortality rates. This
association has led to calls for “powder-free” NICUs and the development of new liquid human milk fortifiers. Unfortunately, one of the challenges of liquid fortifiers is displacement of the volume of mother’s own milk, so that the infant receives less total
volume of human milk. Table 1 provides a comparison of the nutrient content and volume of
human milk displaced by the liquid formulations of several commercial human milk
fortifiers available in North America. Note that the use of the bovine liquid fortifiers means
that 17–50% of the volume ingested is formula. The table also demonstrates the significant
variation in macro and micronutrients among these products.