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NICU guideline identifier

Feeding - handling powdered formula and breast milk with additives

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Use of Ready to Feed (RTF) formula in NICU

Sterile RTF formula should be used instead of powdered infant formula where possible and appropriate, especially in high risk infants. (CDC, USFDA and WHO/FAO)

Use of powdered formula

Individual facilities should identify and follow procedures appropriate for that institution to minimize microbial growth in infant formulas;

  1. Minimizing the holding time, whether at room temperature or while under refrigeration, before a reconstituted formula is fed
  2. If formula needs to be prepared in advance, it should be prepared on a daily basis and kept at 4°C or below.
  3. Minimizing the "hang-time" (i.e., the amount of time a formula is at room temperature in the feeding bag and accompanying lines during enteral tube feeding), with no "hang-time" exceeding 4 hours.
  4. Health professionals should investigate and report sources and vehicles (including powdered infant formula) of cronobacter infection and other Enterobacteriaceae.


Apart from providing immunity through other means - reduces the risk of infection associated with formula preparation and storage, although care needs to be taken with breast milk which has been modified with additives.

The following recommendations and procedures have been developed to minimise risk for our patients

NZMoH, ESPGHAN and International Recommendations Our Situation Recommendation
Written guidelines for preparation and handling of infant formula should be established for hospitals and other institutions, and their implementation should be monitored. Written guidelines for preparation and handling of infant formula
Fluids Room with written guidelines and procedures
Microbiological testing of random infant formula samples
Written guidelines and Fluids Room Procedures which are regularly updated
Continue microbiological testing of random infant formula samples by external lab 
Use liquid formula in Newborn Unit, and Starship Children's Health.
The use of sterile liquid formula is encouraged for healthy newborn infants in maternity wards. 
Preterm formula - RTF
Term fomula - RTF
High energy feeds - Infatrini RTF

Breastmilk fortifier - powder
17% (1 ¼ strength)
Special formulas - powder
Other powdered additives - powder
Liquid products used
Make up only the minimum quantity of fortified expressed breastmilk at a time, e.g. 20 or 50 mls until the size of the feed exceeds this
No alternative, but take extra care not to contaminate and ensure hang time is less than 4 hours
If formula needs to be prepared in advance, it should be prepared on a daily basis and should be kept at 4°C or below for not more than 24 hours Fridges must be <4°C
All formula is refrigerated as soon as it is delivered to the ward or a baby's room
Only enough feed for 24 hours supplied
"Use by" date and time on every feed label
Monitor fridges to ensure kept at 4°C
New feeds delivered by every 24 hours
"Use by" date and time on every feed label
Preparing only a small amount of reconstituted formula for each feeding to reduce the quantity and time that formula is held at room temperature for consumption. Not practical in Newborn Unit, maternity wards or SCH. This would result in greater risk of contamination than the current system
Breastmilk fortifier - does apply to this
No change recommended
No formula preparation at "bed or cot side" unless by parent or caregiver (on a case by case basis)
As above
Minimising the "hang-time" with no "hang-time" exceeding 4 hours.  Our recommended maximum hang time is 4 to 6 hours depending on type of feed.
Consider the enteral tube volume of continuous feeding pump giving sets, e.g. Nutricia (Purple) giving set holds approximately 30 ml, therefore it takes >4 hours (at room temperature) for the baby to receive what is in the bottle if the rate of feed is 7 ml per hour or less.
Maximum hang time for powder based infant feeds or EBM with additives of 4 hours.
Ensure a continuous feeding pump (Medicina Orange Feeding Pump) with low volume giving set is used for all feeds of less than 7 ml per hour.


Invasive cronobacter infection is a rare, devastating disease which mainly affects hospitalised preterm or immunocompromised infants fed powdered infant formula.2-9 Cronobacter infection previously known as enterobacter sakazakii, was recently reclassified into a new genus cronobacter.1 Cronobacter has been known to cause meningitis, septicaemia, and necrotising enterocolitis in neonates.2 3 The incidence of cronobacter infection is low but reported mortality rates are up to 80%. In NZ cronobacter became notifiable in 2005 following the death of a preterm baby in a Waikato neonatal unit (ESR, 2007). One invasive disease case was notified in 2005; an elderly male with peritonitis who was on a renal ward (ESR, 2007). The NZ Ministry of Health has reported that newborn twins contracted Cronobacter spp. (E. Sakazakii) meningitis in the neonatal intensive care unit at National Women's Hospital in 1991. Both babies survived but one suffered brain damage and spastic quadriplegia (NZ MOH, 2005). Since the first case was documented in 1958 there have been around 120 documented cases worldwide and at least 27 deaths (to July 2008).4 The worldwide average annual number of reported invasive Cronobacter infections in infants without pre-existing conditions was 1.5 in 1958 - 2003 (68 cases in 46 years) and 4.3 in 2004 - 2010 (30 cases in 7 years).3

In a recent study 90% of Cronobacter infected infants had received powdered infant formula or human milk fortifier and therefore powdered infant formula products are considered to be high-risk foods for the growth of Cronobacter.3 This study shows that cronobacter can also infect healthy, term infants in the first months of life, even if formula preparation safety instructions are followed.3 Invasive cronobacter infection is extremely rare in exclusively breastfed infants or those fed commercially sterile (ready to feed) formula. Powdered infant formula is subject to stringent hygiene controls and microbial criteria in its manufacture. Current international standards (Codex Alimentarius Commission, 2008) require cronobacter to be absent in 30 samples of 10 grams. A general consensus has been reached by the Codex Alimentarius Commission not to establish a microbial criterion for follow-on formula (CCFH, 2009). This is mostly due to a lack of evidence associating illness with follow-on formula, but also because feeding follow-on formula to infants <6 months old contradicts manufacturers' directions. Unintended use or misuse of follow-on formula has led to calls for clearer labelling and education of caregivers and healthcare professionals regarding the appropriate preparation and use of powdered infant formula and follow-on formula. Cronobacter has been isolated repeatedly from powdered infant formula as recently as 2010.5 Cronobacter are so established and abundant in powdered infant formula dry processing environments that eradication is not considered possible. The manufacture of all infant formula begins with non-sterile nutritional components being made into solution which is then homogenized, and pasteurised, resulting in commercial sterility. Liquid ready to feed formula remains sterile but powdered formula is then dried in a non-sterile environment and further non sterile nutritional components may be added after pasteurisation.

WHO guidelines also recommend that water be boiled and cooled for up to 30 minutes before being added to formula powder to achieve a reconstitution temperature of 70°C, to inactivate all cronobacter.4 Not all organisations agree with this recommendation. In 2002, the FDA and the US Department of Agriculture reversed their own recommendations that health professionals use boiled water to reconstitute formula powder, citing potential loss of heat-sensitive nutrients, changes in some formulas' physical characteristics, inadequate destruction of cronobacter, and injury to personnel preparing formula.4 6 The European Society for Pediatric Gastroenterology, Hepatology and Nutrition, Committee on Nutrition also disagreed with the WHO recommendation because of possible adverse effects on nutrients.7 AAP's current instructions do not recommend boiling water unless the safety of the water source is uncertain. NZFSA and the Ministry of Health have produced advice for managing the risk of cronobacter infection from powdered formula preparation. They do not recommend the use of boiling water. The NZFSA and the Ministry of Health guidelines apply to all infants in a neonatal unit, maternity ward or children's hospital ward. It should also be applied to all healthy term infants for the first two months of life.


  1. Iversen C, Mullane N, McCardell B, et al. Cronobacter gen. nov., a new genus to accommodate the biogroups of Enterobacter sakazakii... International Journal of Systematic and Evolutionary Microbiology 2008;58(Pt 6):1442-7.
  2. Stoll BJ, Hansen N, Fanaroff AA, et al. Enterobacter sakazakii is a rare cause of neonatal septicemia or meningitis in VLBW infants. The Journal of Pediatrics 2004;144(6):821-3.
  3. Jason J. Prevention of invasive Cronobacter infections in young infants fed powdered infant formulas. Pediatrics 2012;130(5):e1076-84.
  4. FAO/WHO. Safe preparation, storage and handling of powdered infant formula:Guidelines. Geneva, Switzerland: WHO Press, World Health Organization; 2007. Available at: Accessed 15/1/2013.
  5. Flores JP, Medrano SA, Sanchez JS, et al. Two cases of hemorrhagic diarrhea caused by Cronobacter sakazakii in hospitalized nursing infants associated with the consumption of powdered infant formula. Journal of Food Protection 2011;74(12):2177-81.
  6. Health Professionals letter on Enterobacter sakazakii infections associated with use of powdered (dry) infant formulas in neonatal intensive care units. April 11, 2002. Revised October 10, 2002. Available at: Accessed May 13, 2012.
  7. WHO/NUT/98.1.Complementary feeding of young children in developing countries: a review of current scientific knowledge. Geneva: World Health Organisation. 1998.
  8. Preparation and Handling of Powdered Infant Formula: A Commentary by the ESPGHAN Committee on Nutrition.
  9. Journal of Pediatric Gastroenterology & Nutrition. 39(4):320-322, October 2004
  10. Inquiry into Actions of Sector Agencies in Relation to Contamination of Infant Formula with Enterobacter Sakazakii Dr P G Tuohy Chief Advisor Child and Youth Health and Dr M Jacobs Director of Public Health, Ministry of Health , March 2005

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Document Control

  • Date last published: 30 April 2015
  • Document type: Clinical Guideline
  • Services responsible: Neonatology
  • Author(s): Barbara Cormack
  • Owner: Newborn Services Clinical Practice Committee
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years