Quality assessment of selected drinkable yoghurt brands sold in Iwo, Osun State, Nigeria

Abstract

Background: Yoghurt is increasingly becoming a popular snack among children, adults and the elderly in Nigeria because of the ease of consumption and digestion. During local fermentation process of milk to produce yoghurt, there are conditions that encourage contamination and unintended adulteration of the yoghurt.

Objective: This study examined the quality of four drinkable yoghurt brands (coded LVY, DDY, FPY and FYY) sold in Iwo metropolis in Nigeria.

Methods: Four different drinkable yoghurt samples in plastic bottles displayed for sale at temperature of 22 - 36 0C were randomly purchased. Physicochemical, proximate; and microbial qualities of the yoghurts were analyzed using standard methods. The data obtained were subjected to statistical analysis.

Results: All the yoghurt samples exceeded 2 months of storage. The pH of ranged from 3.31- 4.23 total titratable acidity 0.28 - 0.88 % and total soluble solids 18.9-38.9%. The fat content ranged from 2.97±0.01 to 9.85±0.01 %; protein 1.37±0.11 to 3.19±0.2 %; moisture 57.4±4.7 to 84.1±2.7 % and ash 0.18±0.02 to 0.43±0.0 %. Fibre was not detected in the samples. The microbial analysis indicated that the FPY had the highest total viable count of 2.7±0.1×10⁶ CFU/ml and staphylococcal of 1.4±0.2×10⁵ CFU/ml counts; the DDY had the highest enteric bacteria of 2.1±0.2×10⁶ CFU/ml; the LVY the highest yeast and mold of 2.6±0.3×10⁶ CFU/ml and lactic acid bacteria (4.5±0.4×10⁵ CFU/ml) counts. Bacterial species isolated included Lactobacillus spp., Proteus spp., Enterococcus faecalis and two fungal species.

Conclusion: The physicochemical and proximate quality of yoghurts analyzed were within international standards but showed high microbial contamination.

Keywords: Yoghurt, local production, quality, microbial load