Prevention & Control
Getting sick with Cronobacter is rare, but infections in babies can be fatal.
When a source of a baby’s Cronobacter infection has been found, nearly all have been associated with consumption of reconstituted powdered infant formula. Powdered infant formula is not sterile. Manufacturers report that, using current methods, it is not possible to eliminate all germs from powdered infant formula in the factory. In some investigations, Cronobacter was found in powdered infant formula that had been contaminated in the factory 1,2. In other investigations, Cronobacter was found in opened containers of powdered infant formula that might have been contaminated at home or elsewhere 1,3.
Babies less than 3 months, infants born prematurely, and infants with weakened immune systems are at the highest risk. Parents or caregivers of these babies may want to take extra precautions to protect against Cronobacter infection by following the recommendations below.
Breastfeedingexternal icon is the best option for feeding your baby. It provides many health benefits and helps prevent many kinds of infections among infants. Almost no cases of Cronobacter infection have been reported among infants who were being exclusively breastfed (meaning, the baby was fed only breast milk and no formula or other foods).
If you use a breast pump, practicing careful hygiene can reduce the risk of germs getting into the milk.
- Read all of the instructions that came with your pump, and make sure you understand the manufacturer’s instructions for handling and cleaning your pump’s flanges, valves, and collection bottles. Learn which parts must be washed and the best method for removing, cleaning, and drying parts that need to be cleaned.
- Clean your baby’s feeding bottles in a dishwasher or by hand.
- In a dishwasher, use hot water and a heated drying cycle.
- By hand, scrub in hot, soapy water in a tub or basin reserved for washing bottles, then rinse well and air dry on a clean rack or dish towel.
- Consider using a bottle sterilizer or boiling the bottles after washing and rinsing them by hand.
- Wash your hands with soap and water before pumping, and be sure anyone preparing bottles or feeding your baby washes their hands with soap and water first.
Liquid formulations of infant formula are made to be sterile and should not transmit Cronobacter infection when handled carefully. To prevent contamination of liquid formula:
- Wash hands with soap and water before preparing bottles or feeding your baby.
- Infant formula does not need to be warmed before feeding, but some people like to warm their baby’s bottle. If you do decide to warm the bottle, never use a microwave. Microwaves heat milk and food unevenly, resulting in “hot spots” that can burn your baby’s mouth and throat.
- To warm a bottle: place the bottle under running warm water, taking care to keep the water from getting into the bottle or on the nipple. Put a couple drops of infant formula on the back of your hand to see if it is too hot.
- Clean your baby’s feeding bottles in a dishwasher or by hand. In a dishwasher, use hot water and a heated drying cycle. By hand, scrub in hot, soapy water in a tub or basin reserved for washing bottles, then rinse well and air dry on a clean rack or dish towel. Consider using a bottle sterilizer or boiling the bottles after washing and rinsing them by hand.
- If your baby does not finish drinking a bottle within 2 hours, throw away the unfinished formula.
Make sure that your formula is not expired or recalled, and that the container is in good condition. Keep powdered formula lids and scoops clean, and close containers of formula as soon as possible. In most cases, it is safe to mix powdered infant formula following manufacturer’s instructions. But if your baby is less than 3 months old, was born prematurely, or has a weakened immune system, you may want to take the following extra steps to prepare your formula with hot water (at least 158°F/70°C) to protect against Cronobacter:
- Clean up before preparation
- Prepare safely
- Keep powdered formula lids and scoops clean (be careful about what they touch)
- Close containers of infant formula as soon as possible
- These steps, when followed correctly, can kill Cronobacter and other bacteria in formula.
- Boil water and let it cool for about 5 minutes before pouring into a clean bottle or feeding cup. Add the exact amount of formula listed on the container, and carefully shake the capped bottle rather than stirring the mixture.
- To use right away, cool the formula to body temperature to ensure it is not too hot before feeding your baby. Run the prepared, capped bottle under cool water or place it into an ice bath. Do not let the cooling water get into the bottle or on the nipple.
- Before feeding the baby, test the formula’s temperature by putting a few drops on the inside of your wrist. It should feel warm, not hot.
- Use quickly or store safely
- Use formula within 2 hours of preparation. If the baby does not finish the entire bottle of formula, discard the unused formula.
- If you do not plan to use the prepared formula right away, refrigerate it immediately and use it within 24 hours2. If you can’t remember how long you have kept formula in the refrigerator, it is safer to throw it out than to feed it to your baby. For more information visit CDC’s Infant Formula Preparation and Storage webpage.
- FAO and WHO. Enterobacter sakazakii (Cronobacter spp.) in powdered formulae: Meeting report. [PDF –
121 pages]pdf iconexternal icon Microbiological Risk Assessment Series 15. 2008. ISBN 978-92-5-106119-0.
- WHO, Food and Agriculture Organization of the United Nations. Guidelines for safe preparation, storage and handling of powdered infant formula. pdf icon[PDF – 32 pages]external icon 2007.
- Always wash your hands carefully with soap and water during key times.
- Before preparing and feeding bottles or foods to your infant.
- Before touching your infant’s mouth.
- Before touching pacifiers or other things that go into your infant’s mouth.
- After using the toilet or changing diapers.
- If soap and water aren’t readily available, use hand sanitizer with at least 60% alcohol. Hand sanitizer can quickly reduce the number of germs on hands in some situations, but they are not a substitute for washing with soap and water.
- It is also important to keep all objects that enter infants’ mouths (such as pacifiers and teethers) clean.
Food Safety and Handwashing:
- WHO: Safe preparation, storage and handling of powdered infant formula guidelines pdf icon[PDF – 361KB]external icon
- Foodsafety.gov: Baby food and infant formulaexternal icon
- Handwashing: Clean Hands Save Lives, hand- and water-related hygiene tips
- Put Your Hands Together [PODCAST – 3:48 minutes], information on how to help stop the spread of infection and stay healthy
- FAO and WHO. Enterobacter sakazakii (Cronobacter spp.) in powdered formulae: Meeting report. pdf icon[PDF – 121 pages]external icon Microbiological Risk Assessment Series 15. 2008. ISBN 978-92-5-106119-0.
- Himmelright I, Harris E, Lorch V, Anderson M. Enterobacter sakazakii infections associated with the use of powdered infant formula—Tennessee.external icon JAMA. 2001;287:2204-5.
- Baumbach J, Rooney K, Smelser C, Torres P, Bowen A, Nichols M. Cronobacter species isolation in two infants—New Mexico, 2008. MMWR Morb Mortal Wkly Rep. 2009;58(42):1179-83.