The cooling and freezing of food products occurs at various points in the manufacturing process. Depending on the product and time and space capacities, this can be done continuously or batch wise. The objectives of the cooling process can be varied: for the hardening of product surfaces, for cooling above the freezing point or for the freezing of the products.
Although freezing is by far one of the best methods for conserving food products, improper slow freezing or an irregular drop in temperature can lead to the creation of large ice crystals and damage to cell walls and muscle fibres. When later defrosted, the food loses a part of the cell liquid and thus suffers loss in nutritional value, taste and consistency. The freezing speed depends, on the one hand on the nature of the product and on the other on the conditions in the freezer. The product itself influences the freezing speed through water content, ingredients, starting temperature, product density and shape, surface type and heat conductivity.