Antibacterial capacity of a reconstituted fortified beverage used as a nutritional supplement
Résumé
A fortified beverage powder intended for developing countries was composed of vitamins, minerals, sugar and orange flavor. Organic acids were also added as food additive. The antibacterial efficacy of reconstituted beverage was tested on three strains of enterobacteria (Escherichia coli, Salmonella Typhi and Serratia liquefaciens). The antibacterial efficacy of beverage containing organic acids (ascorbic and citric acids) as compared to the same beverage containing mineral acid was successfully demonstrated. The greatest inhibitions of bacterial growth were observed in the presence of organic acids. The antibacterial activity was significant depending on initial bacterial concentration and time of contact. However, S. liquefaciens was not detected in the beverage containing organic acids regardless of the bacterial concentration added. At a concentration of 103 cells/mL, the bacterial population of S. liquefaciens, E. coli, S. Typhi and the mixture of the three bacteria reached an undetectable level in the beverage containing organic acids after 5, 180, 180 and 60 min of contact, respectively. The inhibitory effect of pathogenic bacteria was closely related to the reduction of the beverage pH and to the concentration of undissociated organic acids.