The refining period for every type of cheese is a basic element of the proper production process. Following loyally the refining time gives the cheese full flavor and high nutritional quality while at the same time secures the health of the consumers. For example, as far as Feta is concerned, respecting the three month refining period achieves this nutritional safety even if the milk is not pasteurized. The producers cooperating with TerraThessalia through the participatory guarantee system ensure that this required refining period is followed for every produced cheese.