Comparison between E. coli O157:H7 and Bifidobacterium spp. Activity in Almond Pudding Infant Supplemental Food

Almond pudding is a common traditional Iranian complementary food for infants after starting solid foods. Escherichia coli O157:H7 is one of the leading pathogenic microorganisms that cause serious foodborne disease in different populations including infants. The large intestine of breast-fed infants is colonized predominantly by bifidobacteria, which have a protective effect against acute diarrhea. The study objective of this research was to screen the survival characteristics of E. coli O157:H7 as well as four strains of Bifidobacterium subspecies (spp.) in almond pudding. The bacterial strains were studied after three and six hours of incubation at 37 ̊C in-vitro. Luria-Bertani (LB) broth was used as a basic medium for both Bifidobacterium spp. and E. coli experiments in anaerobic and aerobic conditions, respectively. The viability of Bifidobacterium spp. increased from 2.46 ± 0.2 to 6.57 ± 1.3 log10 CFU/ml in low inoculum and from 4.53 ± 0.7 to 7.2 ± 0.4 in high inoculum experiments in 6 hours. However, the growth of E. coli O157:H7 from 3.12 ± 0.2 to 4.99 ± 0.1 log10 CFU/ml was significantly (P < 0.05) lower compared to Bifidobacterium spp. The results illustrate impaired growth of E. coli O157:H7 and enhanced growth of Bifidobacterium spp. in almond pudding. The finding demonstrated that almond pudding in infant’s diet may indirectly enhance the protection against survival and growth of E. coli O157:H7 by increasing the Bifidobacterium spp. populations in infant’s gastrointestinal system.