This Bachelor´s thesis was commissioned by Valio Oy Turenki UHT Plant and its quality control laboratory. The purpose of the thesis was to find out how useful Thermo ScientificTM Nicolet iSTM 50 analyzer and its ATR measurement unit would be in raw ingredient quality control. The aim was to develop a method for the analyzer with which the raw ingredient quality of kids food could be more easily and smoothly controlled in the factory´s laboratory.

Investigated ingredients were flours, vitamin mixtures and vegetable oil mixture used in kids food processing. However, the thesis finally focused on investigating the quality of vegetable oil mixtures as it was an ingredient of which most samples could be collected. The peroxide value is the most common indicator of oil quality and it was chosen to be a factor to be developed for the ATR measurement unit.

The manufacturer’s technical manual, literature about spectroscopy and infrared technology were used in the theoretical part of the thesis. Quality control, sampling, sample processing and legislation concerning kids food were also explored. In the practical part of the thesis samples of investigated ingredients were collected and analyzed with the ATR measurement unit and sent further to be analyzed.

Two key challenges emerged in the study i.e. the relatively small amount of samples and lack of reference results. Reference results would be needed to get more reliable results. As developing a new method, method calibration and validation are ongoing processes, the development of ATR methods should be further continued. Even though the thesis didn´t reach its aims it was proved that as a sampling method ATR is a useful part of smooth quality control.