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Final report of the FAO/WHO Regional Conference on Food Safety for Asia and the Pacific |
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Seminar on Enterobacter sakazakii in Powdered Infant Formula
26 May 2004,
Seremban, Malaysia
A seminar on Enterobacter sakazakii in Powdered Infant Formula was held on May 26, 2004 in Seremban, Malaysia, as a satellite event at the FAO/WHO Regional Conference on Food Safety for Asia and the Pacific. The meeting is of due importance following the joint FAO/WHO workshop on Enterobacter sakazakii and other microorganisms in powdered infant formula, held in Geneva, Switzerland in February 2004. The workshop recognized the need for increased understanding and awareness of E. sakazakii and its consequences.
The overall objectives of the seminar on Enterobacter sakazakii in Powdered Infant Formula was to increase the awareness of E. sakazakii by facilitating the exchange of science-based information, to increase the capacity building efforts related to microbial risk assessment, to share information on current studies and to identify data for future research.
Scientists from industry, academics, and international organizations were invited to give presentations at the seminar. A total of 100 participants from regulatory agencies and health ministries from the Asia Pacific attended the half-day event. The topics discussed include current knowledge and issues on E. sakazakii contamination in infant foods, the minimizing of E. sakazakii contamination in the manufacture of infant formula, prevention of cross-contamination of E. sakazakii during infant formula preparation and present work as well as future research needs on E. sakazakii.
Dr Sally Hasell of New Zealand Milk, New Zealand, opened the seminar with an overview of the microbes’ characteristics. It is known that E. sakazakii is considered as an opportunistic pathogen and can cause disease in all age groups. Infections are uncommon in healthy adults and children, although low birth weight, premature and immuno-compromised infants are more susceptible to E. sakazakii-related infection.
E. sakazakii can be widely found in the environment and foods, and it is probable that soil, water, and vegetables are the principle sources of the bacteria when it is found in food. It is difficult to differentiate E. sakazakii from other closely related bacteria that are often present in the food. Currently there are no internationally validated methods to detect E. sakazakii. The most commonly used methods are those documented by ISO and FDA.
The bacteria can grow at a temperature between 6–47oC. A new research shows that inactivation of the bacteria occurs quickly at temperatures above 70oC. A study has also shown that the bacteria can survive in a dry environment quite well.
Recent outbreaks of severe diseases-like meningitis in at-risk infants have been linked to infant formula consumption, even though the products were generally in conformance with microbiological requirements of the current Codex Code of Hygienic Practices of Foods for Infants and Children.
Contamination of powdered infant formula with E. sakazakii and Salmonella are linked to severe illness in infants, which includes serious developmental sequelae and death. Dr Peter Ben Embarek, World Health Organization (WHO), Switzerland, stated that neonates, especially pre-term infants, low-birth weight infants and immuno-compromised infants are at the greatest risk of E. sakazakii infection.
The current Codex criteria was established many years ago and it needs to be reviewed in view of new developments and knowledge. It is recommended that revision to the current Codex guidelines include replacing coliforms with Enterobacteriaciae as indicators, tightening the limits for Enterobacteriaciae, and adopting different levels according to the age groups.
Low levels of E. sakazakii contamination in powdered infant formula are considered to be a significant risk factor. However, based on a preliminary risk assessment, the inclusion of a pathogenic lethal step at the point of preparation and a decrease in the holding and feeding times would effectively reduce risk.
The food industry is encouraged to take appropriate steps to minimize the concentration and prevalence of E. sakazakii in the manufacturing environment, as well as in the powdered infant formula. It was also recommended that a greater range of commercially sterile alternative formula products be available from the industry for high risk infants.
Dr Anthony Huggett of Nestle, Switzerland, stated that the industry’s experience in eliminating Salmonella from infant formula has provided insights into managing E. sakazakii. Though it is not currently possible to completely eliminate Enterobacteriaceae from manufacturing environments, it is possible to achieve a substantial reduction in the level of Enterobacteriaceae, including E. sakazakii, in infant formula.
As the manufacturing of infant formula included the wet and dry steps, it has been noted that addition of ingredients after heat treatment is a possible source of contamination. It is important that these ingredients must be sterilized prior to addition into the product. Dry cleaning of manufacturing plants has also shown positive results in reducing the presence of E. sakazakii and other bacteria in the final products.
The risks from E. sakazakii can only be mitigated effectively through the implementation of a combination of complementary preventive measures, including limiting the presence of the bacteria in the infant formula and ensuring that the products are used in a way that prevents the introduction or growth of E. sakazakii in the formula prior to infant feeding. This can be achieved by providing clear instructions on the use and preparation of infant formula and providing means for education of caregivers.
In April 2001, a premature infant death in a neonatal intensive care unit in Tennessee, USA was linked to E. sakazakii. This led to an investigation by the Centres for Disease Control and Prevention (CDC), which resulted in policy changes at the hospital in the preparation, storage and administration of infant formula.
Mr Michael Stein of Mead Johnson Nutritionals, Thailand, stated that as of now, there are no internationally-available guidelines concerning infant formula feeding. Recommendations by the CDC are to select formula products based on nutritional needs, and use alternatives to powdered infant products whenever possible. Trained personnel should also prepare powdered infant formula using aseptic techniques in a designated preparation room. The manufacturer’s instructions should be followed and the product should be refrigerated immediately or discarded if not used within 24 hours after preparation. Lastly, the administration or “hang time” for continuous enteral feeding should not exceed 4 hours.
Reference documents were also made available to health care providers, to increase their awareness.
Dr Sri Estuningsih of Bogor Agricultural University, Indonesia, shared the fact that currently, little is known about the ecology, virulence factors, pathogenicity, and prevalence of E. sakazakii in powdered infant formula. There are also no available data about the prevalence of the bacteria in powdered infant formula available in developing countries.
It is important to determine the prevalence of E. sakazakii in infant foods in developing countries through proper reporting and investigation of the sources and vehicles of infections. At the same time, research on pathogenicity and virulence factors of E. sakazakii should be conducted to increase the knowledge of these bacteria, especially in the infant formula. Development of specific and rapid microbiological and molecular detection methods and their respective validation studies should take into consideration, the current situation in developing countries.
The seminar concluded with a discussion session where the participants shared the countries technical constraints and resource limitations in conducting data collection and testing for E. sakazakii. Collaboration between academia and industry scientists to conduct surveys and checks of microbial contamination of commercial infant food products may be explored. A study on hygienic practices and the impact on E. sakazakii in children hospitals may also be a topic to be considered. Public education for mothers and other caregivers having direct contact with infants on the preparation, use and handling of infant formula are also important to reduce E. sakazakii-related infections.
