Effect of Bifidobacterium breve on the growth of Enterobacter sakazakii in rehydrated infant milk formula

The effect of Bifidobacterium breve on the survival and growth of Enterobacter sakazakii in rehydrated infant milk formula stored at 4-45C was studied. A commercial culture of B. breve and a five-strain cocktail E. sakazakii were mixed with rehydrated formula and stored up to 8 h. The populations of B. breve and E. sakazakii at each storage time/temperature were determined. There was a two-way interactive effect between B. breve numbers and temperature on the number of E. sakazakii in the rehydrated formula at 3-8 h of storage. E. sakazakii did not grow in the rehydrated formula at 4C. At 12 and 20C, the numbers of E. sakazakii in the presence of B. breve were lower than those in the formula without B. breve at 8 h of storage, and at 45C, when the bacteria were combined, a similar result was obtained at 6- and 8-h storage. The presence of B. breve in the formula appeared to enhance the growth of E. sakazakii at 37C in the rehydrated formula stored at 2-8 h. Other more competitive inhibitory probiotic cultures would be more appropriate to control E. sakazakii growth in unrefrigerated rehydrated milk-based formula.