Viability of Lactobacillus acidophilus La-5 in the presence of Williopsis saturnus var. suaveolens

Maintaining the viability of probiotic microorganisms from production to consumption has long been a technological challenge for the food industry. The objectives of this study were to evaluate the in vitro interaction between Lactobacillus acidophilus La-5 and Williopsis saturnus var. suaveolens and the effect of this yeast on acidification kinetics, viability of Lactobacillus acidophilus and post-acidification in fermented milk during refrigerated storage at 5 °C. The in vitro study showed a positive interaction between the acid cell free-supernatant (CFS) of probiotic bacteria La-5 and the yeast. The addition of W. saturnus var. suaveolens increased the fermentation time due to consumption of the organic acids produced by L. acidophilus. During the refrigerated storage of the samples, the presence of the yeast increased the viability of L. acidophilus and reduced post-acidification. However, the mechanism of such interaction of bacteria and yeast is not fully understood.