Survival of Cocktail of Lactic Acid Bacteria Isolated from Breast Milk During Powder Infant Formula Reconstitution and Their Ability to Compete with Cronobacter sakazakii

Abstract

Cronobacter sakazakii is an emerging pathogen occasionally found in powdered infant formula (PIF) and causes ilnessess in certain groups of infants. To achieve the minimum risk level of C. sakazakii it is recommended to carry on reconstitution of PIF at temperature of 70 °C or more. The recommended temperature may therefore influence the presence of lactic acid bacteria (LAB) commonly added as probiotic in PIF and other milk powder. The objectives of this study were to determine the antimicrobial activities of cocktail of L. rhamnosus isolated from breast milk against C. sakazakii, to evaluate the effect of the reconstitution temperature towards the survival and growth of L. rhamnosus and C. sakazakii, and to determine the influence of L. rhamnosus on the growth of C. sakazakii after reconstitution. L. rhamnosus cocktail was more effective in inhibiting the growth of single strain C. sakazakii than cocktail of C. sakazakii. The use of cocktail of L. rhamnosus R21 & R25 could inhibit the growth of C. sakazakii YR c3a by 3.75 log CFU/mL. At the same time, the growth of cocktail of L. rhamnosus was not affected by the presence of C. sakazakii. Addition of cocktail of L. rhamnosus R21 & R25 in reconstituted powdered infant formula did not influence the growth of C. sakazakii significantly. Survival of C. sakazakii was influenced by reconstitution temperatures.