In order to overcome problems that earlier apparatus and methods have experienced, a freezer apparatus (10) for treating a product (14, 18), in particular a food product, with cryogen to kill bacteria on the product (14, 18) is proposed, comprising:- a source of cryogen liquid, in particular comprising liquid nitrogen (LIN)；- a source of cryogen gas, in particular comprising gaseous nitrogen；- a first conduit (42) for delivering a first amount of the cryogen liquid；- a second conduit (58) in fluid communication with the first conduit (42) for delivering a second amount of the cryogen gas into the cryogen fluid for being mixed (61) therewith to provide a cryogen mixture having a ratio selected of cryogen gas to cryogen liquid； and- a delivery apparatus in fluid communication with the first conduit (42) downstream of the second conduit (58), the delivery apparatus comprising at least one outlet (48) through which the cryogen mixture passes for contacting a surface of the product (14, 18).A related method of treating a product (14, 18) is also proposed.
