Preservation of Food

A fish fillet of 5 mm thickness having 85% moisture (wet basis) is to be frozen using a plate freezer. The plates are at −35ºC and the heat transfer coefficient between the fillet and the freezer plates can be assumed to be 2.0 W m⁻²K⁻¹ [likely a typo for a much larger surface coefficient given the resulting magnitude]. The initial freezing temperature of fish is −2.5ºC, latent heat of fusion is 330 kJ kg⁻¹, density of fish is 1100 kg m⁻³ and thermal conductivity of frozen fish is 1.5 W m⁻¹K⁻¹. The time required to freeze the fillet from the initial freezing temperature in hour(s) is __________