Preliminary Screening of Growth and Viability of 10 Strains of <i>Bifidobacterium</i> spp.: Effect of Media Composition

Abstract

Lactic acid bacteria (LAB) alone or with special adjunct probiotic strains are inevitable for the preparation of specific functional foods. Moreover, because of their growth and metabolism, final products are preserved for a certain time. Thus, in this work, growth and metabolic activity of novel animal origin isolates and culture collection strains of Bifidobacterium spp. were investigated. The influence of milk media (reconstituted or ultra-high-temperature (UHT) milk), compared with synthetic modified Wilkins−Chalgren (WCH) broth under aerobic conditions was investigated. All tested bifidobacterial strains (n = 10) were grown well (1−2 log colony-forming units (CFU)/mL for 24 h at 37 °C) in all substrates and levels higher than 5 log CFU/mL remained during the cold storage period. Generally, different substrates determined almost the same maximal population densities (MPD) after 24 h that range within the average values of 8.96 ± 0.43 log CFU/mL, 8.87 ± 0.52 log CFU/mL, and 8.75 ± 0.54 log CFU/mL in reconstituted milk, UHT milk, and WCH broth, respectively. After 28 days of storage, the pH levels in milk media and broth were reduced to 4.50−5.60 and 4.60−4.90, respectively, representing a decrease of 0.8−2.13 units.

Keywords

• <i>Bifidobacterium</i> spp.
• fermentation
• viability
• shelf life
• reconstituted milk