The invention relates to a UHT system for heat treating temperature-sensitive food products, in particular desserts or dessert-like products, comprising a pre-heating zone and a subsequent high-heating zone. The aim of the invention is to achieve accurate and fast temperature adjustment of the food product leaving the pre-heating zone to the temperature conditions at the inlet of the high-heating zone in a UHT system of the generic type, and at the same time, with an equal dwell time for all partial amounts of the food product, to ensure that the food product is treated in a particularly thermally gentle manner and to keep the mechanical loading of the food product as low as possible.