In-Line Process and Product Control Using Spectroscopy and Multivariate Calibration

The quality of a product is dynamic in nature and develops over time. We present a case study from the food industry in which the concept of measuring the end-product quality is extended to incorporate the shelf-life period of the product with practical examples showing the harm of ignoring the changes that occur in the product quality as a function of time. The article also addresses the use of in-line spectroscopy to relate the variations in the input parameters, such as the raw materials, and the process variables to the final product quality over the entire shelf-life of the product. We also discuss multivariate statistical process control and monitoring issues.