In order to overcome problems that earlier apparatus and methods have experienced, an apparatus (10) for applying a heat transfer substance, in particular comprising a cryogen, for example comprising liquid nitrogen (LIN), to destroy bacteria, in particular comprising campylobacter, on a product (12), in particular selected from the group consisting of a food product, a carcass, or a combination of food products and carcasses, is proposed, said apparatus (10) comprising: - a housing (16) having an inlet (18), an outlet (22), and a chamber (20) therebetween in communication with the inlet (18) and the outlet (22); - a conveyor (24) constructed and arranged to transport the product (12) through the chamber (20); - a heat sensing apparatus (26, 28, 30; 32, 34, 36) responsive to heat parameters of the product (12) at the inlet (18) and the outlet (22) and able to transmit signals of said heat parameters; - a heat transfer substance spray apparatus (38, 40, 44) in fluid communication with the chamber (20) for providing said heat transfer substance to said chamber (20); and - a controller (52) connected to the heat sensing apparatus (26, 28, 30; 32, 34, 36) and the heat transfer substance spray apparatus (38, 40, 44) for controlling administration of said heat transfer substance to the chamber (20) and the product (12) in response to the signals from said heat sensing apparatus (26, 28, 30; 32, 34, 36). A related method of applying a heat transfer substance is also proposed.