What is Enterobacter sakazakii?
Why is Enterobacter sakazakii
a particular problem for infant formula?
How common is the problem?
We don't know the answer to this as so little information on E. sakazakii is available. However, infant formulas are intrinsically very safe as they are produced to very strict microbiological standards under stringent hygienic conditions. Temperatures used during the processing of infant formulas aim to kill those bacteria that are likely to be present and pose a health risk to babies. However, contamination and/or growth of bacteria can occur when making up the feeds and during subsequent storage.
Does processing destroy the organism?
Pasteurisation destroys E. sakazakii. Liquid ready-to-use infant formulas are commercially sterile. Powdered infant formulas cannot undergo a final sterilisation in pack because this would adversely affect the nutritional quality of the product. However, they are heat-treated (pasteurised) during processing using temperatures that aim to kill all bacteria that are likely to be present and pose a health risk to babies. However, this does not stop contamination and/or bacterial growth occurring later, for example, while making up feeds with water or during subsequent storage. Research confirms that proper temperature control during preparation, usage and storage of infant formulas is important in preventing growth.
QUESTIONS & ANSWERS ON DEPT OF HEALTH ADVICE ON PREPARATION OF FEEDS, AND THE REASONS BEHIND IT
Why are we getting more enquiries about preparation and storage of powdered formulas? The Department of Health (DH) has revised the Birth to Five book (May 05) and the bottle-feeding leaflet (Nov 05) to remove all references to advance preparation of formulas. Mothers are advised to “make up only one feed at a time and throw away any left over milk”. UNICEF UK have followed suit (August 05), but HCPs are looking for the evidence to justify this change. DH/FSA have issued guidance for HCPs on their websites, but this is causing more confusion (December 06)
Why did DH change the Birth to Five book and the Bottle feeding leaflet?
At the end of 2004, the European Food Safety Authority (EFSA) issued an Opinion on the Microbiological Safety of Infant Formulas. EFSA has issued a number of recommendations relating to good hygiene practices in the factory, hospital and home, including advice to use commercial sterile liquid formula in hospitals and advice to parents to use reconstituted formula immediately. The Food Standards Agency (FSA) and DH have assessed this advice, and issued the updated advice to consumers, using these 2 publications. We await the hospital communication.
What do other agencies say?
NHS Direct recommends that carers use “cooled, boiled water” and “feeds should be made up fresh for each feed”.
NCT recommend that members make up feeds at or above 70oC, and suggests practical ways of doing this such as only boiling the required amount of water which will cool more quickly to 70oC in the kettle.
UNICEF UK BFI says that if mothers decide to bottle feed, they will be asked if they want to be taught how to make up a bottle properly, and staff will be able to answer any questions. There is a UNICEF UK BFI bottle feeding leaflet that reflects the FSA advice.
NICE Routine Postnatal Care of Women and their Babies (July 06) says that any woman who wishes to use formula milk should be taught how to make feeds
Why are carers asking about mixing at 70oC?
DH advice recommends that carers leave the kettle for at least 30 minutes. However, the Food Standards Agency website recommends mixing at 70oC. Leaving the kettle for 30 minutes will achieve a temperature of 70oC, but the FSA advice has generated a number of questions from HCPs and carers
Is there a quicker way to cool the boiled water in the kettle to 70oC?
1 litre of water (filling the kettle half full) takes 15 minutes to cool to 70oC
Following the new DH advice, carers are asking how to make up feeds when travelling
Either: Use ready made formula available in 200 or 500ml tetrapacks. This is recommended in the DH Bottle feeding leaflet.
Or: Boil the freshly run tap water, and fill the sterilised feeding bottle(s) to the required level.
Seal with a sterilised cap. Measure out the required number of scoops per feed into a portable sealable container. When the baby is ready to feed, add the powder to the sterilised water, shake well and feed immediately. As long as the baby is fed immediately, it is not necessary to reheat the boiled water.
Or: Store the made up feed for at least 1 hour in the fridge at 5oC before leaving the house, carry the feed in a cool bag with a frozen ice brick, and feed to the baby within 4 hours. This is suggested by DH/FSA but is not the safest option.
Can carers use a flask when travelling?
This is suggested in the DH Bottle feeding leaflet. However we have some concerns about the recommendation to put freshly boiled water into the flask leading to scalding issues when mixing, combined with the possible inability to cool the feed to feeding temperature. Therefore we recommend using the sterilised feeding bottle as the means of carrying the boiled water.
Should the same advice apply to follow-on formulas?
Why aren’t powdered infant formulas labelled to warn that they are not
What advice has the US FDA issued?
What advice has the European Food Safety Authority (EFSA) issued?
EFSA recommends that sterile liquid infant formulas are used wherever available for infants at the highest risk of infection. The following table shows their recommendations for the use of powders:
Why has EFSA recommended 70oC to reconstitute feeds?
Tests have shown that if E.sakazakii were present in very low quantities in the powdered formula, it would be destroyed at this temperature. Therefore, even if the made up formula was incorrectly stored, there would not be a problem with E.sakazakii. However, EFSA also recommend that home carers could safely use water that has been boiled and cooled if fed immediately. We feel this is a more practical option for home carers.
WHO is actively working on worldwide recommendations. The UK FSA is part of the Expert Group looking into the issues. After their last meeting in May 2006, WHO issued draft Guidelines on Safe Preparation, Storage & Handling of Powdered Infant Formulae. These are undergoing stakeholder consultation and we await the results of this consultation. The draft Guidelines recommend mixing all infant formulas at 70oC, but acknowledges that no formulas are currently designed to mix well at this temperature. They also confirm that minimising the time from preparation to consumption reduces the risk, as does storage below 4oC.
I have heard that New Zealand has issued hospital guidelines, what are they?
New Zealand has issued guidelines to all their hospitals that sterile liquid infant formula is recommended for infants at the highest risk of infection.