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Assessing Hot Water Reconstitution Instructions and Labeling of Powdered Infant Formula to Ensure Cronobacter spp.
Maria Amalia Beary1, Sarah E Daly1, Jakob Baker1
1Department of Food Science, Cornell University, Ithaca, NY, USA.
Insights
Cronobacter spp. in powdered infant formula (PIF) poses risks to infants. Heating water to 70°C (158°F) is crucial for safety. This study found that preparation methods significantly impact water temperature, with specific techniques ensuring safe reconstitution temperatures.
Area of Science:
- Food safety
- Microbiology
- Public health
Background:
- Cronobacter spp. contamination in powdered infant formula (PIF) is a serious risk for high-risk infants.
- Current public health guidelines recommend reconstituting PIF with water heated to at least 70°C (158°F) for microbial inactivation.
Purpose of the Study:
- To evaluate how different heating and cooling scenarios during formula preparation affect water temperature.
- To identify preparation conditions that best ensure a minimum treatment temperature of 158°F (70°C) for PIF reconstitution.
Main Methods:
- Investigated the impact of vessel type, lid usage, heat source removal, and water volume on heat retention.
- Assessed the 'hot shot' method (small hot water volume followed by larger cool water volume).
- Analyzed the influence of bottle material, capacity, and water volume on temperature changes.
Main Results:
- Water temperatures frequently dropped below 158°F (70°C) before PIF reconstitution in many tested scenarios.
- Bottle material, capacity, water volume, and initial water temperature significantly affected reconstituted PIF temperature (p < 0.001).
- The 'hot shot' method resulted in temperatures well below the recommended 158°F (70°C).
Conclusions:
- Specific preparation conditions, including bottle type and water volume, significantly influence the final temperature of reconstituted PIF.
- Reconstituting PIF when the hot water in the bottle reaches 165°F (73.8°C) generally results in safe temperatures, but requires 30 seconds of passive cooling.
- Current PIF labeling lacks adequate guidance for caregivers on safe reconstitution practices using hot water.
Abstract:
Cronobacter spp. contamination in powdered infant formula (PIF) can cause infections in high-risk infants. Public health guidelines for caregivers of high-risk infants advise reconstitution of PIF using water heated to at least 70 °C (158 °F) for microbial inactivation. This study evaluated changes to water temperature under different heating and cooling scenarios during formula preparation, aiming to identify which conditions best ensure a minimum treatment temperature of 158 °F (70 °C). Vessel type, lid usage, vessel removal from the heat source, and water volume were tested for their effects on heat retention. The "hot shot" method which uses a small volume of hot water followed by a larger volume of cooled water was also evaluated. In many scenarios, water temperatures fell below 158 °F (70 °C) during the steps prior to PIF reconstitution. The water temperature prior to transfer to the bottle, bottle material, and capacity, and volume of transferred water significantly impacted temperature (p < 0.001). The temperature of formula immediately following shaking was as high as 179.5 ± 1.6 °F (81.9 ± 0.9 °C) and as low as 138.0 ± 1.3 °F (58.9 ± 0.7 °C), depending on the preparation conditions. Bottle material and capacity, water volume, and initial water temperature significantly impacted the temperature of reconstituted PIF. Small volumes (2 fl. oz) of water in small glass bottles cooled the quickest. The hotshot method yielded temperatures well below 158 °F (70 °C). Measuring the temperature of hot water in the bottle and adding PIF when it cooled to 165 °F (73.8 °C) resulted in formula temperatures at or above 158 °F (70 °C) in almost all cases achieving a >5 log CFU/mL C. sakazakii reduction. However, 30 s of passive cooling was required to ensure pathogen lethality. PIF labels were reviewed, and lacked detailed information about how caregivers of high-risk infants should use hot water to reconstitute PIF. Our findings can help shape guidelines that improve PIF reconstitution practices.
