Thermal processing of liquid-like foods

The ice cream liquid mix that you prepared in the lab needs to be pasteurized before freezing. The line will be used to produce 3.8L pails of ice cream. The ice cream will contain about 70% volume of mix, the rest being air. The line must produce 9500 pails per day.

a) Compute the composition of the mix and its thermal properties: Specific heat (cp), thermal conductivity (k), and density ().

b) Calculate the amount of dry saturated steam (6 psig) needed to heat the mix from 4 C to 81 C (i.e., without heat recovery). Compare it to the steam required with heat recovery for a system similar to the one in the figure from the textbook.

c) Compute the time required to provide, at 81 C, a total reduction of 6D for the microorganism that has a D75 value of 17.3 s at 75 C, with z = 5.92 C

d) Discuss how to arrange production to match the production of pails required, i.e., total time required (in hours), how many shifts, size of holding tank for the liquid mix.