Effect of Refrigerated Storage on Sensory Attributes and Microbial Quality of Cow, Goat and Sheep Milk Shrikhand

Abstract

The quality and storage stability of Shrikhand are governed by several factors including milk composition, fermentation conditions, total solids content, microbial activity and post-processing storage conditions. The present study comparatively evaluated the sensory acceptability and microbiological quality of Shrikhand prepared from cow, goat and sheep milk during 35 days of refrigerated storage at 5 ± 1 °C. Milk of each species was standardized to 4.5% fat, fermented using Lb. paracasei ssp. paracasei NCDC 22 up to 0.85% lactic acidity, and processed into Shrikhand. Sensory attributes including colour and appearance, body and texture, flavour, sweetness and overall acceptability were assessed, while microbiological quality was evaluated through lactic acid bacteria (LAB), yeast and mould, and coliform counts. Sensory scores of all Shrikhand samples decreased progressively during refrigerated storage; however, the magnitude of deterioration differed significantly among milk species. Cow milk Shrikhand exhibited comparatively superior sensory stability, with overall acceptability scores decreasing from 8.00 at 0 day to 6.75 at 35 days, followed by sheep milk Shrikhand, which declined from 7.94 to 6.50. Goat milk Shrikhand showed comparatively faster deterioration in flavour, body and texture, sweetness and overall acceptability, with scores decreasing from 7.25 to 6.81 during storage. Overall acceptability scores above 7.0 were maintained up to 28 days in cow and sheep milk Shrikhand, whereas goat milk Shrikhand remained acceptable up to 21 days of storage. LAB counts decreased significantly (p<0.05) during storage in all samples due to progressive acid stress and nutrient depletion. Sheep milk Shrikhand maintained the highest LAB viability throughout storage, decreasing from 7.16 to 4.66 log cfu/g, followed by cow milk Shrikhand (6.18 to 4.05 log cfu/g) and goat milk Shrikhand (6.83 to 3.76 log cfu/g). Conversely, yeast and mould counts increased progressively during storage, reaching maximum levels in goat milk Shrikhand (2.30 log cfu/g at 35 days), indicating comparatively greater fungal susceptibility. Coliform organisms were not detected in any sample throughout storage, confirming satisfactory hygienic quality and effective processing conditions. The results demonstrated that milk species considerably influenced the sensory and microbiological stability of Shrikhand during refrigerated storage.