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खुला एक्सेस

अमूर्त

Growth and Survival of Cronobacter sakazakii in Reconstituted Commercial Infant Milk Formula in the Presence of Bifidobacterium Species

Markus C. Labuschagne*, C.I Raselabe

Aim: We hypothesise that Bifidobacterium bifidum LMG 11041 and Bifidobacterium longum LMG 13197 may inhibit the survival and growth of Cronobacter sakazakii in Reconstituted Infant Milk Formula (RIMF) due to their probiotic properties. The main objective of the study is to determine whether the Bifidobacterium bifidum LMG 11041 inhibits the growth and survival of the enteropathogen Cronobacter sakazakii in RIMF.

Objectives: The specific objectives were to screen commercial infant formula for the presence of Cronobacter sakazakii; to determine the change in levels of Cronobacter sakazakii and Bifidobacterium species in RIMF over a specified period at different temperatures; to determine how the pH of RIMF is affected by the presence of probiotics and pathogens.

Methods: Neonatal bacterial sepsis is one of the leading causes of infant mortality. Among many of the organisms responsible for neonatal sepsis is Cronobacter sakazakii. It is especially dangerous as it has been found to proliferate in powdered Reconstituted Infant Milk Formula (RIMF). The problem is due to prolonged time between reconstitution and administration, allowing the pathogen to multiply to infectious levels. This study determined whether the inclusion of Bifidobacteria species in infant formula can limit the growth and survival of C. sakazakii after reconstitution of the milk.  A 1:1 ratio of a two-strain cocktail of C. sakazakii isolated from RIMF, B. bifidum LMG 11041 and B. longum 13197 was inoculated into RIMF and incubated at different temperatures after which viable numbers of bacteria were determined.

Results: There was no difference in the growth and survival of C. sakazakii in the presence and absence of B. bifidum at all temperatures tested. The numbers of bifidobacteria did however increase. A considerable drop in pH occurred in RIMF inoculated with B. bifidum and C. sakazakii. This effect was not observed when the RIMF was inoculated with C. sakazakii alone. There was no statistically relevant interaction between the numbers of C. sakazakii when incubated in the presence or absence of Bifidobacteria species at the 10% mean difference threshold.

Conclusion: The presence of B. bifidum LMG 11041 or B. longum LMG 13197 in RIMF did not have a statistically relevant inhibitory effect on the survival of C. sakazakii.