Strain- and matrix-dependent survival of Lactobacillus acidophilus LA-5 and Lacticaseibacillus paracasei 431 in commercial ice cream bases

english

2026

volume 23, issue 1

frozen storage   ice-cream   Lacticaseibacillus paracasei   Lactobacillus acidophilus   probiotics

Univerza v Mariboru, Fakulteta za kmetijstvo
(Obvezni izvod spletne publikacije)

The survival of Lactobacillus acidophilus LA-5 and Lacticaseibacillus paracasei 431 was evaluated in commercially available ice cream base mixtures differing in dairy and plant-based fat content. The objective was to determine strain-dependent stability during frozen storage and to model viability loss using the Weibull inactivation equation. Following inoculation, samples were frozen and stored at -20 °C for 90 days. Viable counts were monitored periodically, and survival kinetics were described by non-log linear regression. A significant reduction in cell numbers was observed after a single freeze–thaw cycle in both strains. During subsequent storage, gradual inactivation occurred, with distinct strain- and matrix-dependent differences. L. acidophilus LA-5 showed higher stability in formulations with dairy-based fat compared with the plant-based fat, whereas L. paracasei 431 exhibited shorter predicted times to equivalent log-reductions in dairy systems. Survival curves were adequately described by the Weibull model, indicating heterogeneous resistance within bacterial populations. The results demonstrate marked strain- and formulation specific differences in probiotic stability during frozen storage and provide quantitative parameters for predicting viability loss in ice cream matrices.

21.07.2026