Inactivation of nondesiccated and desiccated Cronobacter Sakazakii and Salmonella spp. at low and high inocula levels in reconstituted infant milk formula by vanillin

Cronobacter sakazakii and Salmonella occur at low levels in infant formula and survive desiccation and known to grow in reconstituted formula to infectious levels causing severe diseases in newborns. This research determined the minimum inhibitory (MIC) and bactericidal (MBC) concentrations of vanillin against nondesiccated and desiccated cocktails of C sakazakii and Salmonella at 4,10 and 23 degrees C in quarter-strength TSBYE. Next, the antimicrobial effect of several vanillin concentrations was tested against nondesiccated and desiccated cells at high and low inocula levels in reconstituted infant milk formula (IMF) at 4, 10 and 23 degrees C. The results showed that nondesiccated C sakazakii and Salmonella were more susceptible to vanillin than desiccated cells at 4, 10, and 23 degrees C in 1/4 TSBYE. At high inoculum level, vanillin inhibited the growth of nondesiccated C. sakazakii and Salmonella in reconstituted IMF at 4,10 and 23 degrees C, but inhibited the growth of desiccated cells at 10 and 23 degrees C. At low inoculum level, vanillin inhibited the growth of nondesiccated and desiccated Salmonella at 4, 10, and 23 degrees C, but inhibited nondesiccated C sakazakii at 4, 10, and 23 degrees C and inhibited desiccated cells at 23 degrees C. Generally, the inhibitory effect of vanillin against low inoculum was greater than that against high inoculum for nondesiccated and desiccated C. sakazakii and Salmonella. Thus, using vanillin as antimicrobial additive can control C sakazakii and Salmonella in IMF. (C) 2014 Elsevier Ltd. All rights reserved.