Probiotic Bacteria as Biological Preservatives for Mango Juices

Abstract

Background: Mango juice is highly perishable and is susceptible to physicochemical deterioration and microbial spoilage during storage. Growing consumer demand for natural and preservative-free foods has encouraged the use of lactic acid bacteria as biological preservation agents. However, comparative information on the preservative performance of Weissella confusa, Levilactobacillus brevis, and Lactiplantibacillus pentosus in mango juice under different storage conditions remains limited. Aims: Preserving the value of tropical fruits poses a significant challenge due to their short shelf life. Driven by shifting consumer preferences toward natural, preservative-free, and nutrient-enriched products, this study aimed to evaluate the potential of the probiotic bacteria Weissella confusa, Lactiplantibacillus pentosus, and Levilactobacillus brevis to preserve fruit juices. Place and Duration of Study: Food Biotechnology and Microbiology Laboratory, Food Science and Technology Research Department, Nangui ABROGOUA University, between March to June 2025. Methodology: 100 mL of juice was inoculated with 10⁵ CFU/mL of each bacterial strain. Juices inoculated were stored at room temperature or in the fridge. pH, titratable acidity, and total soluble solids content were measured. Counts were also performed for yeasts and molds, total and thermotolerant coliforms, mesophilic aerobic microorganisms, and lactic acid bacteria. Results: pH dropped from approximately 4 at day 0 to around 3 at day 28, while titratable acidity increased from approximately 2% at day 0 to a maximum reported value of 8.3% on day 14. Soluble solids content ranged between 3% and 5% across the juices. The lactic acid bacteria remained viable during storage with loads exceeding 106 CFU/mL. All three bacteria inhibited the growth of Staphylococcus aureus. Conclusion: Lactiplantibacillus pentosus, Weissella confusa, and Lactiplantibacillus pentosus remained viable throughout the juice storage period, maintaining counts exceeding 6 log10 CFU/mL. These bacterial strains adapted well to the juices and demonstrated significant metabolic activity through acidification of the medium.