Lactobacillus Cell-Free Supernatants as Clean-Label Biopreservatives for Carabeef: Antimicrobial, Antioxidant, and Quality-Sustaining Efficacy under Refrigerated Storage

Buffalo meat (carabeef) is a nutritionally superior red meat and a globally significant commodity, with India contributing approximately 37% of world production and serving as the largest exporter. However, microbial spoilage and lipid oxidation remain persistent challenges that compromise carabeef quality and safety during storage and export. Growing consumer demand for clean-label, natural preservation alternatives has intensified interest in postbiotic-based biopreservation strategies. This study evaluated the biopreservative potential of cell-free supernatants (CFS) derived from Lactobacillus plantarum MTCC 9496, Lactobacillus rhamnosus MTCC 12920, and Levilactobacillus brevis MTCC 13243 — individually (AB-CFS) and in combination (ABC-CFS) — on the quality and shelf life of carabeef under refrigerated storage for six days.

The minimum inhibitory concentration of both AB and ABC extracts was determined as 32 AU/mL against E. coli ATCC 25922, Listeria monocytogenes ATCC 19118, and Staphylococcus aureus ATCC 6538 using a microtiter broth dilution assay. CFS-treated carabeef maintained significantly lower total plate counts compared to untreated controls and ascorbic acid (0.05%) groups throughout storage, demonstrating superior antimicrobial efficacy attributable to bacteriocins, organic acids, and bioactive peptides. Colour stability was preserved, with b* values — an indicator of lipid-associated discolouration — effectively controlled in CFS-treated groups. CFS treatments maintained pH within the acceptable fresh carabeef range (5.4–5.8) across the storage period. TBARS values remained well within safe limits throughout storage, with ABC-CFS achieving antioxidant efficacy comparable to synthetic ascorbic acid (p > 0.05), attributed to phenolic metabolites and metal-chelating organic acids produced during LAB fermentation.

These findings collectively establish that Lactobacillus CFS, particularly the tri-species combination, is a highly promising, GRAS-compliant, clean-label biopreservative capable of extending carabeef shelf life without compromising sensory or physicochemical quality, with significant implications for sustainable meat preservation during cold chain export.