SHELF-LIFE ANALYSIS OF POTATO MILK AND POTATO YOGURT STORED AT DIFFERENT TEMPERATURES AND VIABILITY OF Lactobacillus brevis IN POTATO YOGURT

Abstract

When manufactured and stored, plant-based milks are unstable and tend to phase separate and degrade over extended periods. Studying the shelf life of milk and yogurt is crucial since it depends on whether they exhibit any physical, chemical, or sensory traits that make them unfit for human ingestion. The probiotics present in yogurt play a significant role in maintaining gut health. However, ensuring the probiotic’s viability and assessing any physical property changes are crucial for fermented products containing probiotics, particularly when a combination of lactic acid bacteria is utilized as the probiotic or starter. Hence, the shelf-life of potato milk and yogurt was assessed by testing for the presence of total coliforms, total bacterial count, total fungal count, Enterococcus sp., Clostridium sp., Pseudomonas sp., E. coli., V. parahemolyticus., V. cholerae., Shigella spp., Salmonella spp., S. aureus, pH, total acidity, syneresis, total soluble solids, and the viability of potato yogurt stored at various temperatures was assessed using standard procedures. Potato milk and potato yogurt stored at room temperature had a shelf life of 1 day. At 15 °C, potato milk had a shelf life of 1 day, and potato yogurt had a shelf life of 2 days. At 10 °C, potato milk and yogurt had a shelf life of 2 days. At 5^oC, potato milk had a shelf life of 4 days, and potato yogurt had a shelf life of 8 days. At -2^oC, potato milk had a shelf life of 13 days, and potato yogurt had a shelf life of 16 days. The viability of L. brevis in potato yogurt stored at room temperature, 15 °C, 10 °C, 5 °C, and   -2 °C remained the same between 10⁷ and 10⁸ cfu/ml.