Methods and devices heat or cool viscous materials, such as meat emulsions useful for producing food and other products. The devices include a heat exchanger including a first plate, a second plate attached to the first plate, and a first spacer and a second spacer arranged between the first plate and the second plate. The first plate, the second plate, the first spacer, and the second spacer define at least one temperature controlled passaged for a product to pass through the heat exchanger. The heat exchanger can be used in a system including one or more of a grinder, a mixing tank, an emulsifier device, a positive displacement pump, or a cutting device.