Intrinsic contamination of powdered formula with E. sakazakii or Salmonella can cause infection and illness in infants, including severe disease, and can lead to serious developmental sequelae and death. Other means for E. sakazakii illness in infants are plausible. A case where sterile formula was contaminated by starch has been documented, but other modes have not been clearly demonstrated. Means of transmission other than powdered infant formula have been demonstrated for infant salmonellosis.
The potential role of other Enterobacteriaceae has not been established but cannot be ruled out, given the limitations of current surveillance systems. While other pathogens (e.g. toxigenic bacteria) have been identified in powdered infant formula, their presence has not been implicated as causing illness in infants.
E. sakazakii has caused disease in all age groups. From the age distribution of reported cases, it is deduced that infants (children <1 year) are at particular risk. The infants at greatest risk from E. sakazakii infection are neonates (<28 days), particularly pre-term infants, low-birth-weight infants or immunocompromised infants. Infants of HIV-positive mothers are also at risk, because they may specifically require infant formula and they may be more susceptible to infection.[14], [15] The latter consideration, as well as low birth weight, may be of particular concern for some developing countries, where the proportion of such infants is higher than in developed countries.
There is a small but finite possibility that one or a small number of organisms in a serving could cause illness. This risk increases rapidly if the level of E. sakazakii is allowed to increase. Low numbers of E. sakazakii in powdered infant formula were also considered to be a significant risk factor, given the potential of even low numbers to multiply during preparation and holding prior to consumption of reconstituted formula.
There is very little known about virulence factors and pathogenicity of E. sakazakii. Phenotypic and genetic studies indicate diversity within the species. There are differences in the microbial ecology of Salmonella and other Enterobacteriaceae. Enterobacteriaceae, such as E. sakazakii, are more commonly found in the manufacturing environment, which serves as the primary source of post-pasteurization contamination. Data from industry and control authorities indicate that the detection of Salmonella in finished powdered infant formula is rare and microbial specifications in the current Codex code are probably adequate, in terms of existing technologies. Specific criteria for Enterobacteriaceae or E. sakazakii are not included in the current Codex code.
Using current mix technology, it does not seem possible to produce commercially sterile powders or to completely eliminate the potential of contamination. Based on a preliminary risk assessment, the inclusion of a bactericidal step at the point of preparation and a decrease in holding and/or feeding time of the reconstituted formula were most effective in reducing risk. A combination of intervention measures had the greatest impact.
Encourage health professionals to investigate and report sources and vehicles (including powdered infant formula) of infection by E. sakazakii and other Enterobacteriaceae. Outbreaks from these organisms are events that should be investigated thoroughly to answer questions about the ecology of these organisms including the dose response.
In situations where the mother cannot breastfeed or chooses not to breastfeed for any reason, alert caregivers of infants - both in the home and in healthcare facilities (particularly those at high risk) - to the fact that powdered infant formula is not a sterile product and that even a product meeting existing Codex standards can be contaminated with pathogens that can cause serious illness.
Develop guidelines for the preparation, use and handling of infant formulas to minimize the risks.
In situations where the mother cannot breastfeed or chooses not to breastfeed for any reason, encourage caregivers of infants, particularly those at high risk, to use, whenever possible and appropriate, commercially sterile formula (e.g. liquid) or formula which has undergone an effective point-of-use decontamination procedure (e.g. heating reconstituted formula).[16]
Encourage industry to develop a greater range of alternative formula products that are commercially sterile for high risk groups.
Encourage industry to reduce the concentration and prevalence of E. sakazakii in the manufacturing environment and powdered infant formula (in a context of risk reduction options).
Encourage industry to use an effective environmental monitoring programme as an important component to an effective environmental management programme.
Promote the use of Enterobacteriaceae rather than coliform testing as an indicator of hygienic control in factories.
Revise the code of practice and related text including the microbiological specifications to better address the microbiological risks of powdered infant formula.
Establish appropriate microbiological specifications for E. sakazakii in powdered infant formula.
Enhance risk communication, training, labelling and educational activities and approaches to ensure awareness of the issue and appropriate point of use procedures for preparation, storage and use of infant formula.
Address the particular needs of developing countries in determining disease burden and establishing effective intervention measures for infants who cannot be breastfed for any reason. This includes determining the effects of external environmental factors on burden of disease, such as inadequate storage facilities (lack of refrigerators), lack of clean potable water, lack of fuel to heat water and unhygienic conditions in milk preparation milieu in home and hospitals. Address the capability of adults to implement control measures in the process of preparation and administration of formula and the capability of laboratory technicians to identify E. sakazakii.
Promote the use of internationally validated detection and molecular typing methods for E. sakazakii and related organisms.
Establish a laboratory-based network to alert authorities of E. sakazakii outbreaks based on standardized reference methods with supporting central laboratory resources and training facilities.
Promote research on ways to reduce the levels of E. sakazakii in reconstituted powdered infant formula, e.g. strict time-temperature control on rehydration, decreasing the time of feeding, addition of inhibitors, use of biopreservatives and acidification and combining treatments.
Promote research to gain a better understanding of the ecology, taxonomy, characteristics and virulence of E. sakazakii. This will be important in underpinning information for the interpretation of epidemiology data and undertaking further risk assessments. The more complex risk assessment initiated in this meeting should be completed and expanded by JEMRA (Joint FAO/ WHO Expert Meetings on Microbiological Risk Assessment).
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[14] The UN guidance for
these infants is that where replacement feeding is acceptable, feasible,
affordable, sustainable and safe, avoidance of all breastfeeding is recommended,
and powdered infant formula may be an option. Some of these infants may be
HIV-positive and thus immunocompromised. [15] As a global public health recommendation, infants should be exclusively breastfed for the first 6 months of life to achieve optimal growth, development and health. Thereafter, to meet their evolving nutritional requirements, infants should receive nutritionally adequate and safe complementary foods while breastfeeding continues until up to 2 years of age or beyond. Infants who are not breastfed require a suitable breastmilk substitute, such as an infant formula prepared in accordance with applicable Codex Alimentarius standards. Information provided in this connection to mothers and other family members who need to use it should include adequate instructions for appropriate preparation and the health hazards of inappropriate preparation and use (WHO, 2002). [16] Nutritional and other factors need to be considered, e.g. alteration of nutritional content, risk from burns due to handling boiling or hot water or formula, and potential for increased risk from germination of bacterial spores. The formula should thereafter be cooled and handled properly. |
