THE USE OF VARIANCE ANALYSIS WITH REPEATE D MEASUREMENTS DESIGNS FOR THE EVALUATION OF NICKEL MIGRATION FROM STAINLESS-STEEL COOKING PANS

The described model statement of a variance analysis with a repeated m easurements design was used for the evaluation of test series, in whic h rhubarb as a corrosive foodstuff was prepared in stainless steel coo king pans with varying cooking/standing time periods (strain time), in order to separate the principal causes of a potential nickel transiti on into the foodstuff. With factory-new pan sets there can actually be detected an increasing nickel pick-up, depending of the time of strai n. However, in reapeated preparings in the same or in other, used pans , the pick-up considerably decreases, and its not any higher than the rhubarb's natural content scattering range. Preparations of rhubarb in the pans obviously entail surface modulations of the steel which in r um minimize a further nickel emitance. Furthermore, the evaluation pre sented allows to assess that one cooking pan manufacturer has carried out measures conserning a pan surface treatment. Finaly the evaluation makes it possible to predict to which extent the inevitable analytic uncertainty may impair the results obtained.