Powdered Infant Formula Samples Research Articles

RESEARCH OF HEAVY METALS, ORGANOCHLORINE AND ORGANOPHOSPHORUS PESTICIDES IN POWDERED INFANT FORMULA

During the period between october 2007 and november 2008 were collected 60 samples of powdered infant formula. The analysis for the detection of heavy metals, organochlorine and organophosphorus pesticides show that the environmental situation is under control and powdered infant formula satisfies this health requisite.

Presence of Soil-Dwelling Clostridia in Commercial Powdered Infant Formulas

Because Clostridium botulinum was isolated from powdered infant formula (PIF) fed to an infant in the United Kingdom who subsequently developed infant botulism and from unopened PIF from the same manufacturer, we tested PIF manufactured in the United States for the presence of clostridial spores. Thirty PIF ingested by 19 California infants with botulism within 4 weeks of onset of illness (48% of all patients fed PIF during study) in 2006-2007 were cultured anaerobically to isolate clostridia. All isolated clostridia were identified to the species level and enumerated with standard microbiologic and molecular methods. Five of 30 (17%) PIF samples ingested by patients contained clostridial spores. Spores were also found in 7 of 9 (78%) market-purchased PIF samples. Clostridium sporogenes was isolated most frequently, followed by Clostridium butyricum and at least 10 other soil-dwelling clostridial species. No neurotoxigenic clostridia were isolated. The most probable number of clostridial spores in PIF ranged between 1.1 to >23 per 100 g. With the notable exception of production of botulinum neurotoxin, C sporogenes is physiologically comparable with proteolytic strains of C botulinum, and both share the same natural reservoir (soils and dust worldwide). The isolation of C sporogenes and potentially pathogenic clostridia from U.S.-manufactured PIF suggests that neurotoxigenic clostridial spores have the potential to be present in these products.

Development of an immobilization and detection method of Enterobacter sakazakii from powdered infant formula

Enterobacter sakazakii is an emerging opportunistic pathogen that is associated with rare but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in premature and full-term infants. In the present study, a procedure was developed for immobilization of E. sakazakii with zirconium hydroxide coupled with detection by a species-specific duplex PCR, based on 16s–23s rDNA internal transcribed spacer (ITS) and ompA gene. Specificity of duplex PCR was tested against two-type strains, six isolates of E. sakazakii and other eight non- E. sakazakii species. When pure culture of E. sakazakii was used for immobilization, total recovery rate ranged from 79.4% to 99.6% of input bacteria, and the detection limit of duplex PCR was 3×10 5 CFU/ml. Different levels of E. sakazakii were inoculated into 90 ml reconstituted powdered infant formula (PIF), and detection limit of duplex PCR was 3×10 0 CFU/ml with 24–30 h enrichment after immobilization. When the experiment was performed in the presence of 10 2 CFU/ml Salmonella typhimurium, the detection limit of duplex PCR was not affected after enrichment. Seven out of 13 commercial PIF were detected positive by duplex PCR after immobilization, while only three were positive by biological methods. This study demonstrates that the combination of immobilization method with duplex PCR is easy, rapid, and efficient, and may have applications for the detection of E. sakazakii in more PIF samples.