Tehran University Medical Journal

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Background: Infant formula, depending on the source, contains various fatty acids, which may possess important nutritional and biological value for infants. The presence of some of these fatty acids in infant formula, however, can be harmful and toxic for the infant. In this regard, more attention has been paid to erucic acid since its accumulation in myocardial tissues may cause damage to the heart. Therefore, a limit has been set by the Codex Alimentarius for the presence of erucic acid in infant formula (less than 1% of total fatty acids). The purpose of the present study is to investigate amount of erucic acid present in three infant formulas used predominantly in Iran.
Methods: Gas chromatography (GC) is a valuable method applied for the separation of fatty acids, including erucic acid, from oils and oily food. Three brands of infant formulas, namely Humana, Biomil and Multi, were analyzed by GC using a wall coated open tubular (WCOT) fused silica column and flame ionization detector (FID). Heneicosanoic acid was employed as an internal standard.
Results: The findings showed that Humana and Biomil infant formula samples contained 0.06% and 0.002% erucic acid (from total fatty acids), respectively, while no erucic acid was detected in the Multi infant formula samples.
Conclusion: The amount of erucic acid in the studied infant formulas was far below the Codex limit of 1% total fatty acids.

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Background: In recent years, use of powdered infant formula (PIF) milk for neonates feed is increasing; therefore, the quality control (QC) of PIF products is very important. The aim of present study was detection of toxigenic Bacillus cereus species in PIF milk using PCR assay.

Methods: The cross-sectional study was carried out on 125 samples of powdered infant formula milk (PIF) purchased between March 2015 and April 2016 in Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Briefly, 0.1 dilutions were prepared and inoculated on Bacillus cereus selective media (MYP) and incubated at 30 °C for 24 hours. The suspicious colonies were verified using biochemical tests based on standard methods. Final confirmation of studied isolates was carried out by ITS gene detection using polymerase chain reaction (PCR) assay. Presence of nonhemolytic enterotoxin (NHE) (linked to diarrhoea syndrome) and emetic toxin (EM) (linked to emetic syndrome) virulence genes were investigated using polymerase chain reaction assay. 

Results: In this study, of 125 PIF samples, 84 (67.2%) were contaminated. Of various recovered bacteria from these samples, 110 bacterial isolates were suspected to be Bacillus spp. using phenotypic methods. The ITS PCR results showed that 91.8% of the isolates were B. cereus. Respectively, 53.63 and 79% of B. cereus isolates possessed NHE and EM virulence genes.

Conclusion: Our data revealed that near 80% of Bacillus cereus isolates have emetic toxin (EM) gene, as result virulence potency of this isolates is very high. However, the low number of this organisms in foods is very important and food safety protocols for these opportunistic toxigenic bacteria should be revised. Since the pasteurization process is ineffective on B. cereus spores; therefore, spores can remain in PIF milk and the vegetative bacterial cells can cause food poisoning in neonates. Therefore, modification of foods quality control protocols is essential in order to identify virulence genes in this bacterium.