Journal of Food Processing & Technology

Abstract

Microbiological Assessment of Some Powdered Infant Formulas: From Quality to Antibiotic Resistance Evaluation

Toscano M, Peroni Diego, De Vecchi E, Mattina R and Lorenzo Drago

Living bacteria are daily used for human consumption as food supplements, also in infant formulas.The amount of ingested viable cells seems to be able to influence the probiotic effectiveness; so it is essential that products available on the market are correctly labelled and that the viability and identity of each strain is ensured. For this purpose, an analysis was conducted on 8 commercial infant formulas to evaluate their stability until the recommended consumption date, the bacterial load and the antibiotic susceptibility of strains used in aforementioned products. Conventional cultural methods were used to isolate and enumerate microorganisms, while their identification was performed by mean of Pyrosequencing. Finally, Minimum Inhibitory Concentrations (MIC) for erythromycin, penicillin, ciprofloxacin and tetracycline were determined using E test. Most of the tested infant formulas were correctly labelled and the number of viable cells remained stable until the recommended consumption date; however, one product did not contain viable cells of one bacterial species reported in the label. Moreover, all products contained strains showing resistance to at least one antibiotic; resistance to tetracycline and ciprofloxacin was rather common among the tested strains. In conclusion, most of the products analysed in this study were correctly labelled and contained a sufficient amount of bacteria. Although, the antibiotic resistance found in all probiotic strains underlined the need for further investigations about the real safety of probiotic strains used as food supplements.