Authors : Adithyan R.; Athira Anilkumar; Kalyani Vijayan; Krishnapriya K. Nair; Devika Lal; Dr. Jubi Jacob

Volume/Issue : Volume 11 - 2026, Issue 5 - May

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DOI : https://doi.org/10.38124/ijisrt/26May041

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Abstract : Yogurt is a nutrient-rich probiotic dairy product produced by fermenting milk with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus [8]. This study compared the microbiological safety and physicochemical properties of commercial yogurt (Sample A) and locally produced yogurt (Sample B) over four weeks. Sample A maintained acceptable microbial quality, with no detectable coliforms or Escherichia coli, indicating proper hygiene and processing. In contrast, Sample B showed higher microbial loads, including coliforms and E. coli, suggesting inadequate sanitation. Proximate analysis revealed that Sample A had stable composition, with protein (7.5–7.6%), fat (~2.14%), and ash (0.90– 0.98%). Sample B showed lower protein (6.6–6.7%), higher fat (~3.0%), and lower ash (0.71–0.78%). Carbohydrate content decreased in both samples due to fermentation, more significantly in Sample B. Moisture increased and solids-not-fat decreased during storage, especially in Sample B, indicating instability. Sample A showed controlled fermentation, with pH decreasing slightly (4.32–4.25) and acidity rising marginally (1.11–1.15%). Sample B exhibited greater changes (pH 4.10– 3.60; acidity 1.70–3.17%), reflecting uncontrolled fermentation. Structural analysis showed better gel quality in Sample A, with lower syneresis (10.76%) and higher water-holding capacity (78.5%). Overall, commercial yogurt demonstrated superior safety and quality.

Keywords : Yogurt; Commercial Yogurt; Probiotic; Microbial Quality; Escherichia Coli; Proximate Composition; Syneresis; Titratable Acidity; Water-Holding Capacity.

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