Establishment of quality criteria and estimate of shelf-life for yogurt beverage and stirred-type yogurt in Korea

This study was conducted to estimate the shelf-life of yogurt beverage and stirred-type yogurt. Samples of yogurt beverage and stirred-type yogurt were stored at 10, 15, and 25°C during 25-day storage, and quality changes were monitored. The quality limit for the sensory evaluation was set to 5 points on a 9-point hedonic scale. The legal limits for other quality criteria were established based on the 'Process Criteria and Ingredient Standards of Livestock Products' issued by the Animal, Plant and Fisheries Quarantine and Inspection Agency (QIA). Regression equations were used to calculate the non-legal quality limits between sensory evaluation (x) and non-legal quality criteria (y). Non-legal quality criteria were excluded from quality criteria used to establish shelf-life which the correlation coefficient (R²) of the regression equation was less than 0. 9. The estimated shelf-life was defined as the date when the earliest date among all date of quality limit. This study indicated that the shelf-life of each sample at 10, 15, and 25°C were as follows: 19, 14, and 12 days for yogurt beverage, and 17, 16, and 12 days for stirred-type yogurt, respectively.