The invention relates to a control system of the chilling process of the temperature of food items at values near but above 0.degree. C. that prevents surface freezing of a food item. The surface freezing can be foreseen due to a mathematical relationship that is a function of the temperature of the food item immediately below its outside surface and of the air temperature near the outside surface of the food item. The above temperatures are detected by a multipoint needle probe. Positioning inside the food item is determined by a projecting member along the needle.