Abstract: The study evaluated the efficacy of crude extracts derived from a nisin-producing strain of Lactococcus lactis ssp. lactis as a bio-preservative to enhance the shelf life of paneer. The investigation employed microbiological analyses and sensory evaluations to determine the optimal concentration of the crude extract. Two treatment groups were established: one with a 50% crude extract (B1) and another with a 100% crude extract (B2). The results indicated that the 100% crude extract (B2) was the most effective treatment, demonstrating significantly lower bacterial, yeast, and mould counts compared to B1. Microbiological assessments revealed that paneer treated with B2 maintained superior microbiological quality throughout the storage period. Total plate counts in the treatment group remained significantly lower (
p<0.01) than in the control group, with a mean of 2.60 and 2.28 for B1 and B2 respectively by day 6, continuing this trend until day 12. While yeast and mould counts remained absent in the control group until day 9, colonies were present within the limits suggested by FSSAI in the treatment group starting from day 6.
Sensory evaluations showed no significant differences (p<0.05) in appearance and colour between the control and treatment groups; however, scores for body, texture, and flavour were superior in the treatment group. For odour, aftertaste, and overall acceptability, control scores were higher after day 9. This study demonstrates that bio-preservation using crude extracts from Lactococcus lactis provides effective preservative action in paneer, maintaining its quality for up to 9 days of storage.
