Antimicrobial activity of lactic acid, acetic acid, and copper on growth of Cronobacter spp. (Enterobacter sakazakii) in laboratory medium and fluid food products

The objective of this study was to determine the effect of lactic acid (0.2%), acetic acid (0.1%) and copper sulfate (50ppm) on the survival and growth E. sakazakii in laboratory medium as well as food products. Bacterial growth was monitored during the incubation period for 8h at 37°C. Lactic acid (0.2%) or acetic acid (0.1%) alone retarded the growth of E. sakazakii. However, the growth of E. sakazakii was significantly inhibited when 0.2 % lactic acid or 0.1% acetic acid in combination with 50 ppm copper sulfate were added into BHI broth and food model. The death rate of E. sakazakii was more rapid in the apple juice samples in the presence of copper in combination with either 0.2% lactic or 0.1% acetic acid. These findings indicated that lactic acid, or acetic acid in combination with copper sulfate, could be used as natural inhibitor for the growth of pathogens.