A Case Study Example
A study of vitamin losses in cereal products provides a practical example of the value of shelf life studies. A cereal product fortified with vitamins A and C was studied to find out what initial levels of these vitamins would need to be added in order to ensure that the product still would meet label claims after six months at 70 F/38%RH. The product was stored at both 70°F and 100°F and vitamin assays performed at intervals over a several week period. The vitamin A degradation reaction is first order which means the rate of change in the vitamin concentration is proportional to its concentration and the vitamin analytical values should be plotted as log values. A preferred method is to convert the analytical values to percent of original level of the vitamin or to a retention ratio of original versus remaining amounts. The log of this value is then plotted versus time. This makes data comparison and table or graph production simpler. A computer spreadsheet program is used to perform this function, figure the log value (fitting the data to the kinetic model), and run regression values From this data one calculates the number of weeks required at the given conditions it would take to lose 25% of the original levels of the vitamins and make recommendations to the developers.