Influence of pH, temperature, and inoculum composition on mixed cultures of Streptococcus thermophilus 404 and Lactobacillus bulgaricus 398

Catherine Béal (1, 2) , Georges Corrieu (2)

1 AgroParisTech
2 GMPA - Génie et Microbiologie des Procédés Alimentaires

The effects of pH, temperature, and inoculum composition on Streptococcus thermophilus 404 and Lactobacillus bulgaricus 398 mixed cultures were studied. Linear quadratic models according to these three variables were proposed to express the growth and acidification characteristics, as well as the final proportion between the two strains. Initial and operating conditions allowing maximization of these characteristics were determined. Finally, a graphic method to predict both final total concentration and final proportion of the two bacteria as a function of pH, temperature and inoculum composition is presented. Key words: lactic acid bacteria mixed cultures population ratio pH temperature

Mots clés: lactic acid bacteria; mixed cultures; population ratio; temperature

Domaines: Sciences du Vivant [q-bio]; Biotechnologies

Catherine Béal, Georges Corrieu. Influence of pH, temperature, and inoculum composition on mixed cultures of Streptococcus thermophilus 404 and Lactobacillus bulgaricus 398. Biotechnology and Bioengineering, 1991, 38, pp.90-98. ⟨hal-03537047⟩