Processes that contribute to radiocesium decontamination of feta cheese.

In a series of experiments, the transfer of radiocesium from ovine milk to feta cheese was investigated through modifications of the standard cheese making procedure. All variations explored showed no significant change in the percentage of radiocesium transfer and the milk-to-cheese transfer coefficient was determined as f=.79 plus/minus .04 L.kg-1. It is concluded that cesium, like the rest of the alkali metals, remains in the water phase and thus follows very closely the distribution of moisture into the products of cheese making. The possibility of radiocesium decontamination of mature feta during the customary storage of the product in brine was also explored in a second series of experiments. The theoretical model employed in the analysis of cesium transport from feta to brine is presented in the Appendix to this paper. Predictions of the model were validated by experiments. A procedure is thus proposed for decontaminating mature feta during storage through successive replacements of the storage medium. Nomograms are presented for the determination of the optimum time interval between changes of the brine and the radiocesium concentration remaining in the feta. Changes in the properties of the product induced by the proposed treatment were also investigated with respect to composition, taste, and overall quality.