Cronobacter Support
07-17-2009, 10:03 AM
5.3.9.2 Preparation
In the home, manufacturers recommend that formula be prepared before each feeding using boiled water. It is recommended to boil the water and then cool it to 50°C before the addition of the measured amounts of the powdered product. Manufacturers recommend that label directions as described above should be followed carefully.
The reasons for the recommendation of cooling the water appear to be threefold. First, there does appear to be some nutrient loss associated with particular formulas, particularly loss of vitamin C. Second, clumping of formula upon rehydration with hot water can occur with certain formula powders. Finally, there are concerns that use of water at elevated temperatures could lead to increased incidence of burns either to the infant or to the formula preparer (the latter being especially pertinent to the inappropriate heating of bottles in microwave ovens). The United States Food and Drug Administration (FDA) provided data (Buchanan, 2003) on nutrient losses associated with rehydrating infant formulas with boiling water. No data were available to the workshop on the effect of the use of hot water on clumping or on burn issues.
After mixing the powder and water by shaking the bottle and cooling it to drinking temperature under water (cheek test), the formula is to be fed to the infant immediately. While rewarming of the bottle cannot be excluded with slow-feeding infants, it should be discouraged. For practical reasons, parents might be tempted to prepare all the bottles needed for one day in advance and keep them in the refrigerator. In this case, rapid cooling of the prepared formula and storage at low temperature are important factors with regard to the microbiological safety of the reconstituted formula.
In hospitals, practices will vary according to local arrangements and availability of trained personnel and facilities.2 A centralized preparation of ready-to-feed formula and on-ward preparation are possible and both have advantages and disadvantages. For both, the availability of safe (sterile) water and aseptic conditions for the preparation are required. The transport of ready-to-feed preparations to the wards under sustained refrigeration and refrigeration on the ward up to the feeding time are important factors to control.
Infants who can coordinate sucking, swallowing and breathing will receive formula from the bottle which has been quickly warmed immediately prior to feeding. Feeding times can be prolonged in sick and hypotonic infants and need to be controlled. Bottles should not be rewarmed. Formula remaining in the bottle should be discarded after a specified time limit.
In the case of immature or sick infants without coordinated sucking/swallowing, feeding by naso- or orogastreal tube or gastrotomy tube is practised. Formula can be applied continuously using a pump or by giving boluses which are adapted in volume to the tolerance of the infant (gastric volume and gastrointestinal motility). Continuous infusion into the gastrointestinal tract by pump requires control of the time of administration of one selected syringe volume as well as observation of the homogeneity of the formula in the syringe. Pre-administrative warming can be omitted. Handling of the infusion system should observe the same precautions as for parental feeding systems. Flushing of the tube after each feeding with sterile solutions may reduce microbial contamination and the formation of biofilms within the feeding delivery systems. Gastric residues of feeds and removed tube systems should be regularly checked for the presence of pathogenic bacteria.
5.3.10 Storage and handling of prepared formula
Farmer et al. (1980) examined 57 strains of E. sakazakii and reported growth of the organism at 25°, 36° and 45°C. Fifty of the tested strains grew at 47°C, but not at 4° or 50°C. Nazarowec-White and Farber (1997b) reported that minimum growth temperatures for E. sakazakii in Brain Heart Infusion (BHI) broth varied from 5.5° to 8°C; and strains actually began to die off slowly at 4°C. In addition, maximum growth temperatures for clinical and food isolates ranged from 41° to 45°C (see also Gavini, Lefebvre, and Leclerc, 1983). This has implications for enrichment broths which have a recommended incubation temperature of 45°C. Iversen, Lane, and Forsythe (2004) and Zwietering (personal communication, 2004) have measured the growth rate of E. sakazakii in powdered infant formula (Figure 6). Generation times for E. sakazakii in reconstituted infant formula varied at 10°C from 4.15 to 5.52 hours and at 22°C from 37 to 44 minutes. Lag times at 10° and 23°C ranged from 19 to 47 hours and 2 to 3 hours, respectively (Nazarowec-White and Farber, 1997b). Iversen, Lane, and Forsythe (2004) examined clinical and food strains and found that the generation times for E. sakazakii in reconstituted infant formula were 13.7 hours, 1.7 hours and 19-21 minutes at 6°, 21° and 37°C, respectively. The relationship between temperature and specific growth rate across the various studies is summarized in Figure 6. Therefore, it is evident that improper storage of contaminated reconstituted powdered infant formula can support rapid growth of E. sakazakii.
It is important to stress that the addition – in hospitals or at home – of ingredients such as starch or sugar to powdered infant formula may present a risk of contamination of the product. Such added ingredients need to comply with the same requirements as the powdered infant formula. However, the specific risk associated with the addition of such ingredients was not considered in this meeting.
5.3.11 Education
Many consumers, including those directly involved in caring for infants, are not aware that powdered infant formula is not a sterile product and may be contaminated with pathogens that can cause serious illness, and they lack information on how handling, storage and preparation practices can influence the risk. Effective risk communication efforts for both the public and health professionals are needed. Information and education about basic hygiene practices in connection with food handling, storage and preparation at home also need to be emphasized.
Figure 6 (attached). Growth rate of E. sakazakii (n=27) in reconstituted powdered infant formula according to temperature (Iversen, Lane and Forsythe, 2004; Zwietering personal communication, 2004).
2 See, for example: Infant feedings; Guidelines for the preparation of formula and breast milk in health care facilities. American Dietetics Association. 2004.
In the home, manufacturers recommend that formula be prepared before each feeding using boiled water. It is recommended to boil the water and then cool it to 50°C before the addition of the measured amounts of the powdered product. Manufacturers recommend that label directions as described above should be followed carefully.
The reasons for the recommendation of cooling the water appear to be threefold. First, there does appear to be some nutrient loss associated with particular formulas, particularly loss of vitamin C. Second, clumping of formula upon rehydration with hot water can occur with certain formula powders. Finally, there are concerns that use of water at elevated temperatures could lead to increased incidence of burns either to the infant or to the formula preparer (the latter being especially pertinent to the inappropriate heating of bottles in microwave ovens). The United States Food and Drug Administration (FDA) provided data (Buchanan, 2003) on nutrient losses associated with rehydrating infant formulas with boiling water. No data were available to the workshop on the effect of the use of hot water on clumping or on burn issues.
After mixing the powder and water by shaking the bottle and cooling it to drinking temperature under water (cheek test), the formula is to be fed to the infant immediately. While rewarming of the bottle cannot be excluded with slow-feeding infants, it should be discouraged. For practical reasons, parents might be tempted to prepare all the bottles needed for one day in advance and keep them in the refrigerator. In this case, rapid cooling of the prepared formula and storage at low temperature are important factors with regard to the microbiological safety of the reconstituted formula.
In hospitals, practices will vary according to local arrangements and availability of trained personnel and facilities.2 A centralized preparation of ready-to-feed formula and on-ward preparation are possible and both have advantages and disadvantages. For both, the availability of safe (sterile) water and aseptic conditions for the preparation are required. The transport of ready-to-feed preparations to the wards under sustained refrigeration and refrigeration on the ward up to the feeding time are important factors to control.
Infants who can coordinate sucking, swallowing and breathing will receive formula from the bottle which has been quickly warmed immediately prior to feeding. Feeding times can be prolonged in sick and hypotonic infants and need to be controlled. Bottles should not be rewarmed. Formula remaining in the bottle should be discarded after a specified time limit.
In the case of immature or sick infants without coordinated sucking/swallowing, feeding by naso- or orogastreal tube or gastrotomy tube is practised. Formula can be applied continuously using a pump or by giving boluses which are adapted in volume to the tolerance of the infant (gastric volume and gastrointestinal motility). Continuous infusion into the gastrointestinal tract by pump requires control of the time of administration of one selected syringe volume as well as observation of the homogeneity of the formula in the syringe. Pre-administrative warming can be omitted. Handling of the infusion system should observe the same precautions as for parental feeding systems. Flushing of the tube after each feeding with sterile solutions may reduce microbial contamination and the formation of biofilms within the feeding delivery systems. Gastric residues of feeds and removed tube systems should be regularly checked for the presence of pathogenic bacteria.
5.3.10 Storage and handling of prepared formula
Farmer et al. (1980) examined 57 strains of E. sakazakii and reported growth of the organism at 25°, 36° and 45°C. Fifty of the tested strains grew at 47°C, but not at 4° or 50°C. Nazarowec-White and Farber (1997b) reported that minimum growth temperatures for E. sakazakii in Brain Heart Infusion (BHI) broth varied from 5.5° to 8°C; and strains actually began to die off slowly at 4°C. In addition, maximum growth temperatures for clinical and food isolates ranged from 41° to 45°C (see also Gavini, Lefebvre, and Leclerc, 1983). This has implications for enrichment broths which have a recommended incubation temperature of 45°C. Iversen, Lane, and Forsythe (2004) and Zwietering (personal communication, 2004) have measured the growth rate of E. sakazakii in powdered infant formula (Figure 6). Generation times for E. sakazakii in reconstituted infant formula varied at 10°C from 4.15 to 5.52 hours and at 22°C from 37 to 44 minutes. Lag times at 10° and 23°C ranged from 19 to 47 hours and 2 to 3 hours, respectively (Nazarowec-White and Farber, 1997b). Iversen, Lane, and Forsythe (2004) examined clinical and food strains and found that the generation times for E. sakazakii in reconstituted infant formula were 13.7 hours, 1.7 hours and 19-21 minutes at 6°, 21° and 37°C, respectively. The relationship between temperature and specific growth rate across the various studies is summarized in Figure 6. Therefore, it is evident that improper storage of contaminated reconstituted powdered infant formula can support rapid growth of E. sakazakii.
It is important to stress that the addition – in hospitals or at home – of ingredients such as starch or sugar to powdered infant formula may present a risk of contamination of the product. Such added ingredients need to comply with the same requirements as the powdered infant formula. However, the specific risk associated with the addition of such ingredients was not considered in this meeting.
5.3.11 Education
Many consumers, including those directly involved in caring for infants, are not aware that powdered infant formula is not a sterile product and may be contaminated with pathogens that can cause serious illness, and they lack information on how handling, storage and preparation practices can influence the risk. Effective risk communication efforts for both the public and health professionals are needed. Information and education about basic hygiene practices in connection with food handling, storage and preparation at home also need to be emphasized.
Figure 6 (attached). Growth rate of E. sakazakii (n=27) in reconstituted powdered infant formula according to temperature (Iversen, Lane and Forsythe, 2004; Zwietering personal communication, 2004).
2 See, for example: Infant feedings; Guidelines for the preparation of formula and breast milk in health care facilities. American Dietetics Association. 2004.