In a plate freezer, the plate temperature is maintained at -25 °C. Latent heat of crystallization is 335 kJ kg⁻¹, and the thermal conductivity and density of frozen meat are 1.25 W m⁻¹ K⁻¹ and 1060 kg m⁻³, respectively. Assuming freezing point of deboned meat at 85% water content on wet basis to be 0 °C, the freezing time in minutes for 2 cm thick block of meat, kept between a pair of freezing plates, is _______.