Effect of non-dairy food matrices on the survival of probiotic bacteria during storage

Abstract

The viability of probiotics in non-dairy food products during storage is required to meet content criteria for probiotic products. This study investigated whether non-dairy foods could be matrices for probiotics. Selected probiotic bacteria were coated on non-dairy foods under two storage conditions, and viabilities were assessed. The non-dairy foods were coated with 5–7 log cfu g⁻¹ of Lactobacillus acidophilus ATCC4356T, Lactobacillus plantarum RC30, and Bifidobacterium longum ATCC15707T. The coated non-dairy foods were stored at 20 °C and 20% relative humidity (RH) or 30 °C and 50% RH. Viability of probiotic bacteria was determined after 0, 2, and 4 weeks of storage. B. longum showed the highest survival at week 4 of 6.5–6.7 log cfu g⁻¹ on wheat bran and oat, compared with 3.7–3.9 log cfu g⁻¹ of L. acidophilus and 4.2–4.8 log cfu g⁻¹ of L. plantarum at 20 °C 20% RH. Under the storage conditions of 30 °C 50% RH, survival of 4.5 log cfu g⁻¹ of B. longum was also found on oat and peanut. This was two and four times higher than the population of L. acidophilus and L. plantarum, respectively. The results suggest that probiotics can survive on non-dairy foods under ambient storage conditions. However, the storage conditions, food matrices, and probiotic strains should be carefully chosen to maximize probiotic bacteria survival.