Stability of freeze-dried starter and non-starter lactic acid bacteria for application in Sicilian cheese making

Abstract

This study developed freeze-dried starter and non-starter lactic acid bacteria (LAB) cultures from traditional Sicilian dairy products to support reproducible artisanal cheese production. LAB viability was monitored over 180 days at various temperatures, with 4 degrees C yielding the best preservation. Lactococcus lactis subsp. lactis showed strong resilience, while Pediococcus acidilactici was more sensitive. After six months, strains were tested in fresh ovine "Tuma" cheese. Microbiological and acidification data revealed that L. lactis strains promoted rapid microbial growth and acidification, reaching pH < 5.0 within 48 h. In contrast, Pediococcus acidilactici, Streptococcus macedonicus, and Lactococcus garvieae showed slower growth and weaker acidification. LAB counts, pH trends, and polymorphic profile comparison confirmed the dominant role of starter cultures in early cheese development, while adjunct strains developed more slowly. In fact, LAB strains influenced Tuma cheese aroma, acidity, sweetness, and overall liking, with L. lactis producing the most balanced and preferred sensory profile. Freeze-drying proved effective for stabilizing LAB cultures, supporting their use in Sicilian cheese making.